Easy Breakfast Casserole Recipe | Make-Ahead Egg Bake
Breakfast casserole is the ultimate make-ahead breakfast solution for busy families, holiday mornings, brunch gatherings, or meal prep Sundays. This hearty, savory dish combines all your breakfast favorites - eggs, cheese, bread, and your choice of meat - into one convenient pan that feeds a crowd with minimal effort.
What makes breakfast casserole so beloved? It's incredibly versatile, completely customizable to your tastes, and can be assembled the night before and simply baked in the morning. No more standing over the stove flipping individual eggs and pancakes while your guests wait! This casserole bakes hands-free while you enjoy your coffee, set the table, or spend quality time with family.
Whether you're hosting overnight guests, planning a holiday brunch, prepping breakfast for the week, or simply want a filling breakfast that reheats beautifully, this recipe delivers. The combination of fluffy eggs, melted cheese, savory meat, and golden bread creates comfort food at its finest. Best of all, leftovers taste just as delicious reheated throughout the week.
This foolproof recipe includes step-by-step instructions, make-ahead options, and four popular variations from classic sausage to vegetarian-friendly options. Let's learn how to make the best breakfast casserole you've ever tasted!
Prep Time: 15 minutes
Cook Time: 45 minutes
Total Time: 1 hour (plus optional overnight chilling)
Serves: 8-10
Difficulty: Easy
Cuisine: American, Breakfast
Diet: Can be made vegetarian
Make-Ahead Friendly: Yes - assemble the night before!
Freezer-Friendly: Yes
Ingredients
Classic Sausage Breakfast Casserole:
For the Base:
1 pound breakfast sausage (pork, turkey, or chicken)
8 large eggs
2 cups whole milk
1 teaspoon salt
1/2 teaspoon black pepper
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
1/4 teaspoon dry mustard powder (optional, adds great flavor)
For the Layers:
6 cups cubed bread (French bread, sourdough, or white bread, cut into 1-inch cubes)
2 cups shredded cheddar cheese (divided)
1/2 cup diced bell pepper (red, green, or both)
1/4 cup diced onion
2 green onions, sliced (for garnish)
For Greasing:
Butter or cooking spray
How to Make Breakfast Casserole
Instructions:
Prepare your baking dish: Grease a 9x13-inch baking dish generously with butter or cooking spray. This ensures easy serving and cleanup. Set aside.
Cook the sausage: Heat a large skillet over medium-high heat. Add the breakfast sausage, breaking it up with a wooden spoon into small crumbles. Cook for 8-10 minutes, stirring occasionally, until the sausage is fully cooked and no longer pink. The sausage should be nicely browned with some crispy bits.
Sauté the vegetables: If there's excess grease in the pan (more than 1-2 tablespoons), drain it off. Add the diced bell pepper and onion to the same skillet with the cooked sausage. Sauté for 3-4 minutes until the vegetables are softened and fragrant. Remove from heat and let cool slightly while you prepare the egg mixture.
Prepare the bread cubes: If using fresh bread, cut it into 1-inch cubes. You'll need about 6 cups total. Day-old or slightly stale bread works even better because it absorbs the egg mixture without getting too soggy. If your bread is very fresh, you can lightly toast the cubes in a 300°F oven for 5-7 minutes.
Make the egg mixture: In a large mixing bowl, whisk together the eggs, milk, salt, black pepper, garlic powder, onion powder, and dry mustard powder if using. Whisk vigorously for about 30 seconds until the mixture is smooth, well combined, and slightly frothy. This ensures even distribution of seasonings.
Layer the bread: Spread the bread cubes evenly across the bottom of your prepared baking dish. They should cover the entire bottom in a relatively even layer.
Add the sausage and vegetables: Distribute the cooked sausage, peppers, and onions evenly over the bread layer. Make sure it's spread out so every serving gets a good mix of ingredients.
Add the cheese: Sprinkle 1 1/2 cups of the shredded cheddar cheese over the sausage and vegetable layer, reserving 1/2 cup for topping.
Pour the egg mixture: Slowly and evenly pour the egg mixture over the entire casserole, making sure to cover all the bread cubes. Use a spatula or your hands to gently press down on the bread to help it absorb the liquid. You want all the bread submerged in the egg mixture.
Cover and refrigerate (optional but recommended): Cover the dish tightly with plastic wrap or aluminum foil. Refrigerate for at least 2 hours or overnight. This allows the bread to fully absorb the egg mixture and makes the casserole extra fluffy. If you're in a hurry, you can skip this step and bake immediately, but let it sit for at least 15 minutes before baking.
Preheat the oven: When ready to bake, preheat your oven to 350°F (175°C). Remove the casserole from the refrigerator and let it sit at room temperature while the oven preheats (about 10-15 minutes).
Add final cheese topping: Remove the cover and sprinkle the remaining 1/2 cup of cheese evenly over the top.
Bake uncovered: Place the uncovered casserole in the preheated oven and bake for 45-50 minutes. The casserole is done when the eggs are set (no longer jiggly in the center), the top is golden brown, and an instant-read thermometer inserted in the center reads 160°F.
Check for doneness: Insert a knife in the center - it should come out clean with no liquid egg. The edges should be golden and slightly pulling away from the sides of the dish.
Rest before serving: Remove from the oven and let the casserole rest for 5-10 minutes before cutting. This allows it to set up properly and makes slicing much easier.
Garnish and serve: Sprinkle with sliced green onions for color and fresh flavor. Cut into squares and serve hot with your favorite breakfast sides!
Variation 2: Vegetarian Breakfast Casserole
Ingredient Modifications:
Omit: Breakfast sausage
Add: 2 cups mixed vegetables (mushrooms, spinach, zucchini, tomatoes)
Add: 1/2 cup diced red bell pepper
Add: 1/2 cup diced yellow or orange bell pepper
Optional: 1/2 cup cooked and crumbled vegetarian sausage
Cheese: Use 2 cups shredded cheese (try a mix of cheddar and mozzarella)
Instructions:
Grease your 9x13-inch baking dish.
Heat 1 tablespoon olive oil in a large skillet over medium heat.
Sauté diced onions and all peppers for 3-4 minutes until softened.
Add sliced mushrooms and cook for 5 minutes until they release their moisture and it evaporates.
Add fresh spinach and cook just until wilted, about 2 minutes. If using zucchini, add it with the mushrooms.
Season vegetables with 1/2 teaspoon salt, 1/4 teaspoon pepper, and 1/2 teaspoon Italian seasoning.
Layer bread cubes in the baking dish, then distribute the cooked vegetables evenly.
Sprinkle with 1 1/2 cups cheese.
Whisk together eggs, milk, and seasonings, then pour over everything.
Press down gently to ensure bread absorbs the liquid.
Cover and refrigerate overnight (or let sit 15 minutes minimum).
Top with remaining cheese and bake at 350°F for 45-50 minutes until golden and set.
Garnish with fresh herbs like parsley or basil before serving.
Variation 3: Ham and Cheese Breakfast Casserole
Ingredient Modifications:
Replace: Breakfast sausage with 2 cups diced ham (about 1 pound)
Cheese: Use 2 cups shredded Swiss or Gruyere cheese instead of cheddar
Optional add: 1/2 teaspoon Dijon mustard to egg mixture
Optional add: 1/4 cup chopped fresh chives
Instructions:
Grease your 9x13-inch baking dish.
If using deli ham, dice it into 1/2-inch pieces. If using a ham steak, cube it.
Heat 1 tablespoon butter in a skillet and sauté the diced onion and bell pepper until softened, about 4-5 minutes.
Add the diced ham to the skillet and cook for 2-3 minutes just to warm through and lightly brown the edges. Remove from heat.
Layer bread cubes in the prepared dish.
Distribute the ham and vegetable mixture evenly over the bread.
Sprinkle with 1 1/2 cups of the Swiss or Gruyere cheese.
Whisk eggs, milk, salt, pepper, garlic powder, and Dijon mustard if using.
Pour the egg mixture over everything, pressing down gently.
Cover and refrigerate overnight or let sit for 15 minutes.
Top with remaining 1/2 cup cheese and chopped chives.
Bake at 350°F for 45-50 minutes until puffed, golden, and set in the center.
The Swiss cheese will create a beautiful golden-brown top.
Serve hot with fresh fruit on the side.
Variation 4: Southwest Breakfast Casserole
Ingredient Modifications:
Sausage: Use 1 pound spicy breakfast sausage or chorizo
Cheese: Use 2 cups Mexican cheese blend or pepper jack
Add: 1 (4-ounce) can diced green chiles, drained
Add: 1 cup corn kernels (fresh, frozen, or canned and drained)
Add: 1 cup black beans, rinsed and drained
Peppers: Use a mix of red and green bell peppers
Seasonings: Add 1 teaspoon cumin and 1/2 teaspoon chili powder to egg mixture
For Serving:
Salsa
Sour cream
Sliced avocado or guacamole
Fresh cilantro
Lime wedges
Instructions:
Grease your 9x13-inch baking dish.
Cook the chorizo or spicy sausage in a skillet, breaking it into crumbles. Cook until fully browned, about 8-10 minutes.
Add diced onions and peppers to the sausage and cook for 3-4 minutes.
Stir in the corn and black beans, cooking just until heated through, about 2 minutes. Remove from heat.
Layer bread cubes in the baking dish.
Distribute the sausage, vegetable, corn, and bean mixture evenly over the bread.
Sprinkle with drained green chiles and 1 1/2 cups of the Mexican cheese blend.
Whisk eggs, milk, salt, pepper, cumin, and chili powder together.
Pour over the casserole and press down gently.
Cover and refrigerate overnight or let sit 15 minutes minimum.
Top with remaining cheese before baking.
Bake at 350°F for 45-50 minutes until golden and set.
Let rest 5 minutes, then top with fresh cilantro.
Serve with salsa, sour cream, avocado slices, and lime wedges on the side.
Variation 5: Bacon and Cheddar Breakfast Casserole
Ingredient Modifications:
Replace: Sausage with 1 pound bacon, cooked and crumbled
Cheese: Use sharp cheddar cheese for maximum flavor
Optional add: 1/2 cup sour cream mixed into egg mixture for extra richness
Optional add: 2 tablespoons chopped fresh chives or parsley
Instructions:
Cook bacon in a large skillet or on a baking sheet in the oven until crispy. Drain on paper towels, then crumble or chop.
Reserve 1 tablespoon bacon grease and use it to sauté the onions and peppers until softened.
Follow the main recipe, layering bread, then bacon, vegetables, and cheese.
If using sour cream, whisk it with the eggs and milk until smooth.
Pour egg mixture over everything and refrigerate overnight.
Bake as directed until golden and puffy.
The bacon adds a wonderful smoky flavor that pairs perfectly with sharp cheddar.
Chef's Tips & Pro Secrets:
Best bread choices: Day-old French bread, sourdough, or crusty Italian bread work best. They hold up to the egg mixture without getting mushy. Avoid soft sandwich bread unless it's a few days old.
Dry out fresh bread: If your bread is very fresh, cut it into cubes and spread on a baking sheet. Bake at 300°F for 5-7 minutes to dry it out slightly. This prevents a soggy casserole.
Make it ahead: This casserole is designed to be assembled the night before! The overnight rest allows the bread to fully absorb the egg mixture, resulting in a more cohesive, fluffier casserole.
Don't skip the resting time: Whether you make it ahead or bake immediately, the bread needs at least 15 minutes to soak up the egg mixture. Overnight is best, but 15 minutes minimum is essential.
Customize the meat: Swap sausage for bacon, ham, chorizo, or turkey sausage. You can also make it meatless by adding more vegetables or vegetarian sausage crumbles.
Cheese varieties: Cheddar is classic, but try Swiss, Gruyere, Monterey Jack, pepper jack, or a Mexican cheese blend. Use a mix of cheeses for more complex flavor!
Prevent soggy bottom: Make sure your bread cubes are relatively dry and that you don't use too much milk. The ratio in this recipe is tested for perfect texture.
Check for doneness: The center should be set (not jiggly), edges should be golden brown, and an instant-read thermometer should read 160°F when inserted in the center.
Freeze for later: This casserole freezes beautifully! Assemble completely, cover tightly with plastic wrap and foil, and freeze for up to 3 months. Thaw overnight in the refrigerator, then bake as directed (may need an extra 5-10 minutes).
Individual portions: Assemble in muffin tins for grab-and-go breakfast portions! Reduce baking time to 25-30 minutes.
Serving size flexibility: This recipe easily feeds 8-10 people. For a smaller crowd, halve the recipe and use an 8x8-inch or 9x9-inch baking dish. Baking time remains the same.
Prevent overbrowning: If the top is browning too quickly but the center isn't set, tent loosely with aluminum foil and continue baking.
Nutrition Information (Per Serving - 1/10 of recipe):
Calories: 385
Protein: 22g
Carbohydrates: 22g
Fiber: 1g
Sugar: 4g
Fat: 22g
Saturated Fat: 9g
Cholesterol: 210mg
Sodium: 780mg
Calcium: 20% DV
Iron: 12% DV
Vitamin A: 15% DV
Health Benefits - Making Breakfast Casserole Healthier:
While breakfast casserole is definitely an indulgent dish, it provides substantial protein from eggs and meat, which keeps you satisfied for hours. Eggs are nutritional powerhouses containing all nine essential amino acids, choline for brain health, and vitamins A, D, E, and B12.
To make this recipe healthier, try these swaps: use turkey sausage or chicken sausage instead of pork, increase vegetables and reduce meat, use whole wheat bread for added fiber, substitute half the milk with unsweetened almond milk, reduce cheese by 1/2 cup, or use reduced-fat cheese. The vegetarian version packed with colorful vegetables adds antioxidants, vitamins, and fiber.
This casserole is also excellent for meal prep - having a high-protein breakfast ready to reheat helps prevent unhealthy grab-and-go choices during busy mornings.
Frequently Asked Questions (FAQ):
Q: Can you make breakfast casserole the night before?
A: Absolutely! In fact, it's better when made ahead. Assemble completely, cover tightly, and refrigerate overnight. The bread absorbs the egg mixture and the flavors meld beautifully. Just bake in the morning as directed.
Q: How long does breakfast casserole last in the fridge?
A: Properly stored in an airtight container, breakfast casserole lasts 4-5 days in the refrigerator. Reheat individual portions in the microwave for 1-2 minutes.
Q: Can you freeze breakfast casserole?
A: Yes! Freeze either before or after baking. To freeze unbaked: assemble, wrap tightly in plastic and foil, freeze up to 3 months. Thaw overnight, then bake. To freeze baked: cool completely, portion, wrap well, freeze up to 3 months. Reheat from frozen or thawed.
Q: Why is my breakfast casserole watery?
A: Common causes: too much milk in the egg mixture, vegetables that released water (always sauté vegetables first to remove moisture), not enough bread to absorb liquid, or not baking long enough. Make sure the center reaches 160°F.
Q: Can I use different types of bread?
A: Yes! French bread, sourdough, Italian bread, ciabatta, or even croissants work great. Avoid very soft sandwich bread unless it's stale. Whole wheat bread adds nutrition and works well too.
Q: How do you reheat breakfast casserole?
A: Microwave individual portions for 1-2 minutes. For larger portions, reheat in a 350°F oven covered with foil for 15-20 minutes. You can also reheat slices in a toaster oven.
Q: Can breakfast casserole be made without bread?
A: Yes! You can make a crustless version using just eggs, meat, cheese, and vegetables. It's like a large frittata. Reduce milk to 1 cup and bake for 35-40 minutes.
Q: What can I serve with breakfast casserole?
A: Fresh fruit salad, hash browns, toast, mixed greens salad, sliced avocado, salsa and sour cream (for Southwest version), or simple roasted tomatoes. Coffee and orange juice complete the meal!
Q: How many eggs do I need for breakfast casserole?
A: For a 9x13-inch pan serving 8-10 people, use 8 large eggs. The ratio is generally 1 egg per serving, plus extra for the bread layer.
Q: Can you make breakfast casserole in a slow cooker?
A: Yes! Grease your slow cooker, layer ingredients as directed, cook on LOW for 4-5 hours or HIGH for 2-3 hours until eggs are set. Great for overnight cooking or keeping warm for brunch!
Storage & Meal Prep Instructions:
Refrigerator - Unbaked: Assemble casserole completely, cover tightly with plastic wrap or foil, refrigerate up to 24 hours before baking. Remove from fridge 15 minutes before baking.
Refrigerator - Cooked: Cool completely, cut into portions, store in airtight containers for 4-5 days. Reheat individual portions as needed.
Freezer - Unbaked: Assemble in a disposable aluminum pan, wrap tightly with plastic wrap then heavy-duty foil. Label and freeze up to 3 months. Thaw overnight in refrigerator before baking. May need 5-10 extra minutes baking time.
Freezer - Cooked: Cool completely, cut into portions, wrap individually in plastic wrap then foil, or use freezer containers. Freeze up to 3 months. Thaw overnight or reheat from frozen.
Meal Prep Strategy: Make 2-3 casseroles at once! Keep one for the week, freeze the others for busy mornings. You'll always have a homemade breakfast ready.
Reheating from Frozen:
Microwave: 3-4 minutes on 50% power, then 1-2 minutes on high
Oven: Thaw overnight, then reheat at 350°F for 15-20 minutes covered with foil
Troubleshooting Common Problems:
Casserole is too dry? You may have used too much bread or not enough egg mixture. Add an extra egg and 1/4 cup milk next time.
Casserole is too wet/runny? You used too much milk or didn't bake long enough. Make sure it reaches 160°F in the center. Also, always sauté vegetables first to remove excess moisture.
Top is browning too fast? Cover loosely with aluminum foil and continue baking until center is set.
Casserole won't slice cleanly? Let it rest for 10 minutes after baking - it needs time to set up. Also make sure it's fully cooked in the center.
Bread cubes are floating? Gently press them down into the egg mixture before refrigerating. They'll absorb liquid and settle.
What to Serve with Breakfast Casserole:
Fresh fruit salad or berry bowl
Hash browns or breakfast potatoes
Simple mixed greens salad
Sliced avocado or guacamole
Salsa and sour cream (for Southwest version)
Toast or biscuits
Roasted cherry tomatoes
Mimosas, coffee, or fresh orange juice
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