Cheesy Christmas Breakfast Casserole

The aroma of melted cheese, sizzling bacon, and baked eggs is a magical way to start Christmas morning. A Christmas breakfast casserole brings that festive feeling straight to the table, creating a warm, cozy atmosphere for family and friends to gather around. It’s hearty, comforting, and just the kind of dish that makes holiday mornings feel extra special.

One of the best things about a holiday breakfast casserole is how flexible it can be. You can layer in your favorite breakfast staples—eggs, cheese, sausage, or even vegetables—making it a dish everyone will love. It’s perfect for feeding a crowd without the stress of juggling multiple pans on the stove, which is why it’s become a favorite in Christmas casserole recipes.

This recipe also works beautifully as a make-ahead Christmas breakfast casserole. You can assemble it the night before, cover it, and refrigerate it overnight, so all you have to do on Christmas morning is pop it in the oven. Overnight breakfast dishes like this make holiday mornings more relaxed, giving you more time to enjoy hot cocoa, exchange gifts, or simply soak in the festive energy with your loved ones.

Whether you’re planning a small family breakfast or hosting a holiday brunch, this casserole is a standout. It’s simple enough for even the busiest holiday mornings yet impressive enough to feel like a special treat. If you’re hunting for Christmas morning breakfast ideas or easy Christmas breakfast ideas that deliver both flavor and convenience, this casserole is the answer.

Why You’ll Love It

• Stress-Free Mornings – This casserole can be prepared the night before, so Christmas morning is all about enjoying time with family instead of scrambling in the kitchen.
• Feeds a Crowd Easily – Whether it’s a small family breakfast or a big holiday gathering, this dish stretches to serve everyone without extra effort.
• Flavor Packed – Layers of cheese, eggs, and your favorite breakfast ingredients combine for a rich, savory flavor that hits all the comfort food notes.
• Versatile Ingredients – You can customize it with sausage, bacon, vegetables, or even leftover ham, making it perfect for a personalized holiday breakfast casserole.
• Perfect for Overnight Breakfast Prep – Assemble it ahead of time, refrigerate overnight, and bake in the morning—giving you a warm, golden breakfast without the morning rush.

Ingredient List

For the Casserole

• 8 large eggs
• 2 cups whole milk
• 1 teaspoon salt
• ½ teaspoon black pepper
• 1 teaspoon Dijon mustard (optional, but adds a subtle zing)

For the Filling

• 2 cups shredded cheddar cheese
• 1 cup cooked breakfast sausage, crumbled
• 1 cup cooked bacon, chopped
• 1 small onion, finely diced
• 1 red bell pepper, diced
• 2 cups day-old bread, cubed (any hearty bread works)

For Topping

• ½ cup shredded mozzarella
• 1 tablespoon fresh parsley, chopped (optional, for a pop of color)

Ingredient Notes

• I always use sharp cheddar for that rich, melty flavor—it makes the casserole extra comforting.
• Don’t skip the bread cubes! They soak up the custard perfectly and keep the casserole fluffy.
• Bacon and sausage can be swapped or combined depending on your taste—more bacon, more happiness.
• The Dijon mustard is optional but trust me, it adds a subtle depth that takes this holiday breakfast casserole to the next level.
• For a colorful touch, the red bell pepper is a simple way to make it look festive without adding much prep time.

Kitchen Equipment Needed

• 9×13-inch Baking Dish – Perfect for layering all the ingredients; I love using a glass dish so I can see the casserole bake.
• Mixing Bowl – To whisk eggs, milk, and seasonings together; I always use a medium glass bowl.
• Whisk – For a smooth, lump-free egg mixture.
• Frying Pan – To cook sausage, bacon, and sauté veggies; non-stick works best for easy cleanup.
• Cutting Board & Knife – For chopping onions, peppers, and bread cubes.
• Measuring Cups & Spoons – For accurate ingredients; my favorite set is magnetic and keeps everything together.
• Aluminum Foil – Optional, for covering the casserole if baking from refrigerated overnight.

Instructions

Step 1: Prepare the Ingredients

• Preheat your oven to 350°F (175°C).
• Dice the onion and red bell pepper into small pieces.
• Cube the bread into roughly 1-inch pieces.
• Cook the bacon until crisp, then chop into small pieces.
• Cook the sausage until browned and crumbly. Drain any excess fat.

Pro Tip: If your bread is fresh, toast it lightly for 5 minutes. It helps soak up the egg mixture without turning mushy.

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Step 2: Whisk the Egg Mixture

• In a medium mixing bowl, combine the eggs, milk, salt, pepper, and Dijon mustard (if using).
• Whisk continuously until fully combined and smooth.

Pro Tip: Whisk in a circular motion and make sure there are no streaks of egg whites left. This keeps your casserole creamy and uniform.

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Step 3: Layer the Casserole

• Grease your 9×13-inch baking dish lightly with butter or non-stick spray.
• Spread the cubed bread evenly on the bottom.
• Sprinkle the cooked sausage and bacon evenly over the bread.
• Add the diced onions and bell peppers on top.
• Pour the egg mixture evenly over everything.
• Sprinkle the shredded cheddar cheese over the top.

Pro Tip: Press down gently on the layers so the bread soaks up some of the custard—this ensures a soft, fluffy center.

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Step 4: Bake the Casserole

• Cover the dish loosely with aluminum foil.
• Bake in the preheated oven for 30 minutes.
• Remove the foil, sprinkle mozzarella on top, and bake for an additional 15–20 minutes, until the cheese is melted and the casserole is set in the center.

Pro Tip: Insert a toothpick in the center—if it comes out clean, the casserole is perfectly cooked.

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Step 5: Make-Ahead & Overnight Option

• Assemble the casserole as directed but don’t bake.
• Cover tightly with plastic wrap and refrigerate overnight.
• In the morning, remove the plastic wrap, cover with foil, and bake for 45–50 minutes. Remove the foil for the last 10 minutes to melt the top cheese.

Pro Tip: Let the casserole sit for 5–10 minutes before slicing—it helps it hold together and makes serving easier.

Tips and Tricks for Success

• Use Day-Old Bread – Fresh bread can get soggy; day-old bread soaks up the egg mixture perfectly.
• Don’t Overcook – Keep an eye on the casserole in the last 10 minutes; overbaking can make it dry.
• Even Layers – Spread ingredients evenly for consistent flavor in every bite.
• Add Veggies Last – Place softer vegetables on top so they don’t get too mushy while baking.
• Let It Rest – Allow 5–10 minutes before slicing for a clean, neat serving.
• Make Ahead – Assemble overnight for a stress-free holiday morning; it bakes just as beautifully the next day.

Ingredient Substitutions and Variations

• Cheese Swap – Use pepper jack, Swiss, or a mix of cheeses instead of cheddar for a new flavor.
• Meat Alternatives – Replace sausage or bacon with ham, turkey sausage, or even cooked shredded chicken.
• Vegetable Additions – Spinach, mushrooms, or zucchini can be added for extra nutrients and color.
• Bread Options – Brioche, sourdough, or even croissants add a richer texture.
• Dairy Alternatives – Swap whole milk for half-and-half or almond milk for a lighter or dairy-free option.

Serving Suggestions

• I love serving this Christmas breakfast casserole with fresh fruit—strawberries and orange slices add a bright, refreshing contrast to the cheesy richness.
• Pair it with hot coffee or cocoa for a cozy, comforting holiday morning.
• Serve alongside buttery croissants or toast—the flakiness balances the soft, custardy casserole perfectly.
• Top with a dollop of sour cream or Greek yogurt for extra creaminess and a tangy twist.
• For a festive touch, sprinkle fresh herbs like parsley or chives just before serving—it makes it look and taste extra special.

Storage and Reheating Instructions

• Refrigerate Leftovers – Cover tightly and store for up to 3–4 days.
• Freeze for Later – Wrap individual slices in foil or store the whole casserole in an airtight container for up to 2 months.
• Reheat in Oven – Bake at 350°F (175°C) for 15–20 minutes until heated through.
• Reheat in Microwave – Place a slice on a microwave-safe plate, cover loosely, and heat for 1–2 minutes, checking for warmth.
• Tip for Best Texture – Avoid overheating to keep the casserole from drying out; a gentle reheat keeps it soft and cheesy.

Frequently Asked Questions

Can I make this casserole ahead of time?

Absolutely! You can assemble it the night before, cover tightly, and refrigerate. Bake it in the morning for a stress-free holiday breakfast.

Can I use different meats or skip them entirely?

Yes! Swap sausage or bacon for ham, turkey sausage, or shredded chicken—or leave out the meat for a vegetarian-friendly version.

What kind of bread works best?

Day-old bread like brioche, sourdough, or even croissants works best. Fresh bread can get a bit soggy.

Can I freeze the casserole?

Yes! Freeze individual slices or the whole casserole in an airtight container for up to 2 months. Reheat in the oven or microwave.

How do I know when it’s done baking?

Insert a toothpick in the center—if it comes out clean and the cheese is melted on top, it’s ready.

Can I add extra vegetables?

Definitely! Spinach, mushrooms, zucchini, or bell peppers all work beautifully. Just keep in mind softer veggies go on top to avoid getting too mushy.

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Did you try this recipe? Let me know in the comments how it turned out! I’d love to hear your favorite twists on this holiday breakfast casserole.