This easy breakfast casserole is a warm, hearty, and comforting breakfast made with fluffy eggs, breakfast sausage, shredded cheese, and soft pieces of bread. Everything bakes together in one dish, making it an easy option for busy mornings, weekend brunches, holidays, and family gatherings.
You can prepare it ahead of time and simply bake it when you’re ready, which makes this recipe especially convenient when you’re feeding a crowd.
Why You’ll Love This Breakfast Casserole
- Easy one-dish breakfast
- Great for feeding a family
- Can be prepared ahead of time
- Uses simple ingredients
- Packed with eggs, sausage, bread, and cheese
- Perfect for weekend brunch
- Great for Christmas and holiday mornings
- Easy to customize with vegetables and different cheeses
Ingredients
- 8 large eggs
- 2 cups whole milk
- 1 teaspoon Dijon mustard
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
- 1/2 teaspoon garlic powder
- 6 cups cubed day-old bread
- 1 pound breakfast sausage
- 1 1/2 cups shredded cheddar cheese
- 1/2 cup shredded Monterey Jack cheese
- 1/2 small yellow onion, finely diced
- 1/2 cup diced bell pepper
- 2 tablespoons chopped fresh parsley, optional
Optional Add-Ins
- Chopped spinach
- Mushrooms
- Diced tomatoes
- Green onions
- Cooked bacon
- Diced ham
- Jalapeños
How to Make Breakfast Casserole
1. Prepare the Baking Dish
Preheat your oven to 350°F.
Lightly grease a 9×13-inch baking dish with butter or nonstick cooking spray.
Set the dish aside.
2. Cook the Sausage
Place a large skillet over medium heat.
Add the breakfast sausage and cook, breaking it into small pieces with a wooden spoon.
Continue cooking until the sausage is browned and fully cooked.
Transfer the sausage to a plate lined with paper towels to remove excess grease.
3. Cook the Vegetables
Using the same skillet, add the diced onion and bell pepper.
Cook for approximately 3 to 4 minutes, until the vegetables begin to soften.
Remove from the heat.
4. Prepare the Egg Mixture
In a large bowl, whisk together the eggs, milk, Dijon mustard, salt, black pepper, and garlic powder.
Whisk until the eggs are fully combined and the mixture looks smooth.
5. Assemble the Casserole
Spread the cubed bread evenly across the bottom of the prepared baking dish.
Add the cooked sausage and sautéed vegetables.
Sprinkle the cheddar and Monterey Jack cheese evenly over the top.
Pour the egg mixture slowly over everything.
Press down gently with a spatula or the back of a spoon to help the bread absorb some of the egg mixture.
6. Let It Rest
For the best texture, allow the assembled casserole to rest for about 10 to 15 minutes before baking.
If you’re preparing it ahead of time, cover the dish and refrigerate it overnight.
7. Bake
Cover the casserole loosely with aluminum foil.
Bake for approximately 30 minutes.
Remove the foil and continue baking for another 15 to 20 minutes.
The center should be set and the top should be lightly golden.
8. Rest Before Serving
Remove the casserole from the oven and let it rest for about 10 minutes.
Sprinkle with fresh parsley or sliced green onions if desired.
Cut into squares and serve warm.
What Bread Is Best for Breakfast Casserole?
Day-old bread works particularly well because it has less moisture and can absorb the egg mixture without becoming overly soggy.
Good choices include:
- French bread
- Sourdough
- Brioche
- Italian bread
- White sandwich bread
- Whole wheat bread
Cut the bread into bite-sized cubes before adding it to the casserole.
Can I Make Breakfast Casserole Ahead of Time?
Yes.
That’s one of the best things about this recipe.
Assemble the casserole the night before, cover it tightly, and refrigerate it overnight.
The next morning, take it out of the refrigerator while the oven preheats.
Bake according to the recipe, adding a few extra minutes if necessary because the casserole starts cold.
Tips for the Best Breakfast Casserole
Use day-old bread. Slightly dry bread absorbs the egg mixture beautifully.
Don’t skip the resting time. It gives the bread time to absorb the custard.
Drain excess sausage grease. This keeps the casserole from becoming greasy.
Use freshly shredded cheese. It melts smoothly and gives the casserole a better texture.
Don’t overbake. Remove the casserole once the center is set.
Let it rest before cutting. Ten minutes helps the casserole hold together when sliced.
Easy Breakfast Casserole Variations
Bacon Breakfast Casserole
Replace the sausage with cooked, crumbled bacon.
Ham and Cheese Breakfast Casserole
Use diced cooked ham instead of sausage and add extra cheddar cheese.
Veggie Breakfast Casserole
Skip the meat and add spinach, mushrooms, bell peppers, onions, and tomatoes.
Mexican-Style Breakfast Casserole
Add cooked chorizo, Monterey Jack cheese, jalapeños, and a little salsa.
Hash Brown Breakfast Casserole
Replace the bread with frozen shredded hash browns.
Use the hash browns directly from frozen and increase the baking time as needed.
Spinach and Feta Breakfast Casserole
Add fresh spinach and crumbled feta cheese for a flavorful meat-free version.
Can I Use Different Cheese?
Absolutely.
Cheddar is classic, but many cheeses work well.
Try:
- Monterey Jack
- Pepper Jack
- Mozzarella
- Colby
- Swiss
- Gruyère
- Feta
You can also combine two different cheeses for extra flavor.
How Do I Know When It’s Done?
The center should look set rather than liquid or jiggly.
Insert a knife into the center.
It should come out mostly clean without a large amount of liquid egg mixture.
The internal temperature should reach 160°F for food safety.
Why Is My Breakfast Casserole Watery?
A watery casserole can happen when vegetables release too much moisture or when the casserole isn’t baked long enough.
Cook watery vegetables such as mushrooms, spinach, onions, and peppers before adding them.
If using frozen vegetables, thaw and drain them thoroughly.
Also make sure the center of the casserole is fully set before removing it from the oven.
How to Store Leftover Breakfast Casserole
Allow the casserole to cool and refrigerate leftovers in an airtight container.
Store in the refrigerator for up to 4 days.
Reheat individual portions in the microwave or warm larger portions in the oven.
Can I Freeze Breakfast Casserole?
Yes.
Allow the casserole to cool completely.
Cut it into individual portions and wrap each piece tightly.
Place the portions in a freezer-safe container or bag.
Freeze for up to 2 months.
Thaw overnight in the refrigerator before reheating.
What to Serve With Breakfast Casserole
This casserole is filling on its own, but it pairs beautifully with lighter sides.
Try serving it with:
- Fresh fruit
- Strawberries
- Blueberries
- Orange slices
- Avocado
- Green salad
- Toast
- Fresh coffee
- Orange juice
For a weekend brunch, serve it alongside fresh fruit and a simple green salad.
Frequently Asked Questions
Can I prepare this casserole the night before?
Yes. Assemble it completely, cover it, and refrigerate overnight. Bake it the following morning.
Can I use sausage links?
Yes. Cook them thoroughly, then slice or crumble them before adding them to the casserole.
Can I make it without meat?
Absolutely. Add extra vegetables and cheese for a delicious vegetarian version.
Can I use frozen hash browns?
Yes. Frozen hash browns can replace the bread. Make sure to follow the package instructions and allow additional baking time if needed.
Can I use milk instead of heavy cream?
Yes. This recipe uses whole milk, which provides a good balance of richness without making the casserole overly heavy.
Can I make individual breakfast casseroles?
Yes. Divide the ingredients among greased ramekins and reduce the baking time. Begin checking them early because smaller portions cook faster.
Recipe Card
Easy Breakfast Casserole
Prep Time: 20 minutes
Cook Time: 50 minutes
Resting Time: 10 minutes
Total Time: 1 hour 20 minutes
Servings: 10
Cuisine: American
Course: Breakfast, Brunch
Ingredients
- 8 large eggs
- 2 cups whole milk
- 1 teaspoon Dijon mustard
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
- 1/2 teaspoon garlic powder
- 6 cups cubed day-old bread
- 1 pound breakfast sausage
- 1 1/2 cups shredded cheddar cheese
- 1/2 cup shredded Monterey Jack cheese
- 1/2 small yellow onion, diced
- 1/2 cup diced bell pepper
- 2 tablespoons fresh parsley, optional
Instructions
- Preheat oven to 350°F and grease a 9×13-inch baking dish.
- Brown the breakfast sausage in a skillet and drain excess grease.
- Sauté the onion and bell pepper until slightly softened.
- Whisk eggs, milk, Dijon mustard, salt, pepper, and garlic powder.
- Add bread cubes to the baking dish.
- Top with sausage, vegetables, and shredded cheese.
- Pour the egg mixture evenly over the casserole.
- Rest for 10 to 15 minutes, or cover and refrigerate overnight.
- Cover with foil and bake for 30 minutes.
- Remove foil and bake another 15 to 20 minutes.
- Rest for 10 minutes before slicing.
- Garnish with parsley and serve warm.
Final Thoughts
This breakfast casserole is one of those recipes that makes busy mornings much easier.
I especially love preparing it the night before. In the morning, all you have to do is put it in the oven while you make coffee and get the rest of breakfast ready.
The combination of fluffy eggs, savory sausage, melted cheese, and tender bread makes every bite comforting and satisfying.
It’s perfect for a relaxed Sunday breakfast, holiday morning, or weekend brunch with family and friends.
From my kitchen to yours, enjoy! ❤️
— Mary