Let’s make this heart and stomach-filling Christmas breakfast casserole everyone will love. I’m calling this a Christmas Breakfast Casserole–but really it’s suitable for ANY holiday or time when you need to feed guests!

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Did you grow up eating casserole breakfasts on Christmas morning? This recipe will become a new family favorite and one you’ll want to make year after year. It packs savory flavors into every bite, and the best part is that it doesn’t demand much prep time.

Prepare the casserole and let it chill in the refrigerator overnight. This frees up my hands on Christmas morning (or any of the busy mornings when you need to feed a crowd!), so I can focus on other holiday tasks.

The savory bread pudding style of this dish delivers comforting goodness first thing on Christmas morning. Let’s make it together and enjoy every bite.

Why You’ll Love This Make-Ahead Breakfast Casserole

My family adores a baked casserole breakfast when we’re all at home, be it a French toast casserole or a sausage breakfast casserole. I love this Easy Breakfast Egg Casserole, but this Christmas breakfast casserole is heartier.

Following are the reasons you’ll love this casserole on busy mornings like Christmas:

Less Morning Work: I make this overnight breakfast casserole on Christmas Eve, place it in the fridge, and head to bed. The next morning, I bring it to room temperature, pop it in the oven, and bake it until it’s golden brown.
Feeds a Crowd: I add a hearty bacon (and sometimes sausage mixture) with plenty of eggs to ensure everyone gets a filling slice. This is a great option for special events when the whole family sits down together.
Flexible Ingredients: You can switch between fresh bread and shredded hash browns depending on what’s in the kitchen. I have used pepper jack cheese for a mild kick or used a milder cheddar—this savory dish tastes great either way.
Easy Process: You brown the meat in a large skillet, whisk eggs in a bowl, and layer everything. It’s a simple recipe that never stresses you out.
Consistent Results: I rely on this casserole to come out perfect every single time. Even when I adapt it, it bakes up just right, which is one of the best things about it.

Recipe Ingredients–What You Need

I love this hearty breakfast casserole because it’s fulfilling and loaded with flavors. Here are the main ingredients needed for this make-ahead casserole:

Croissants: I use day-old croissants for their buttery texture, which holds up well, absorbing all the egg and milk mixture.
Uncured Bacon: It adds a smoky flavor that’s fundamental to the rich taste of the casserole.
Yellow Onion: Diced finely, it brings a sweet, aromatic depth that complements the savory elements.
Large Eggs: They are the glue that binds all the ingredients. We use 14 in this recipe so that’s added a lot of nutrients! Remember–eggs are nature’s multivitamin. 🤓
Whole Milk: It helps create a creamy texture in the casserole. You can add a bit of heavy cream if you’d like, as well, but I usually don’t.
Fresh Parsley: Chopped for a pop of color and a fresh, herby flavor. Dried parsley works, too.
Salt
Black Pepper
Sharp White Cheddar: I go for freshly shredded for its bold taste and how easy it is to melt.

Ways to Customize this Christmas Breakfast Casserole Recipe

If you don’t like bacon and want a casserole with a different type of cheese or meat, no stress. From breakfast sausage to leftover ham and loads of bell peppers, you can do a lot of creativity. Here are some ways to customize this fulfilling casserole:

Change the Meat: You can turkey sausage or black forest ham instead of bacon for a lighter or smokier touch. Both taste great when combined with eggs and give a slight twist to the flavor profile.
Try Different Breads: While I really love using croissants here, feel free to use white bread for a classic base or gluten-free breads if someone in the family needs that option. Using cubed bread gives a hearty texture, and going for a hashbrown breakfast casserole style with shredded hashbrowns is another angle.
Adjust the Cheese: I use sharp cheddar cheese or other varieties. If I want a mild hint of color, I toss in a few cups of cheese that melt well. A subtle blend works beautifully.
Add Some Veggies: I chop a red pepper or two and toss them into the mix; I have also included spinach and mushrooms to the casserole.
Spice It Up: A dash of hot sauce or a sprinkle of herbs can offer extra flavor. I can also serve it in individual portions so everyone can top theirs the way they like.

Step-By-Step Instructions for Making an Overnight Christmas Breakfast Casserole

Butter the bottom of the casserole dish very well. (A large, 4-quart casserole dish works best)
Place the croissant pieces in the bottom of the buttered dish.
In a large skillet, cook the bacon and onions together until the onions are soft and the bacon is cooked. Use a slotted spoon or slotted spatula to remove the bacon and onions (without the grease) and place them on top of the croissant pieces.
Next, add the shredded cheese to the top of the croissant pieces and bacon and onion mixture.
In a medium bowl or large liquid measuring cup, whisk together the eggs, milk, parsley, salt, and pepper. Pour this mixture over the entire casserole dish.
Cover the casserole tightly with plastic wrap and aluminum foil. Place in the refrigerator overnight.
Take the casserole out of the fridge to sit at room temperature while the oven is preheating. Remove the plastic wrap and foil. Preheat the oven to 375 degrees.
Place the foil back on the casserole and bake for 40 minutes on the middle rack. Remove the foil and bake an additional 15 minutes, until the casserole is browned and bubbling.
Let the casserole sit for 15 minutes, then slice into square and serve. Enjoy!

FAQs

Can I prepare this casserole ahead of time?

Of course–that’s what it’s designed for! Assemble the casserole the night before, cover it tightly, and store it in the refrigerator. The next morning, let it come to room temperature before popping it in the oven. It can even stay in the refrigerator for 24 hours before baking if you need to prepare it even sooner than the night before.

What can I use instead of bacon if I want a vegetarian option?

Swap the bacon for a vegetarian alternative like smoked tempeh or just add more vegetables like mushrooms or bell peppers for that meaty texture.

Is this casserole suitable for freezing?

Yes, this casserole freezes well. Cool it completely, slice, and store it in airtight containers. Reheat in the oven or microwave when ready to enjoy.

If you try this Christmas Breakfast Casserole recipe, or any of my healthy recipes, please leave a star rating below! It’s so helpful for other readers to see which recipes are tried and true! I’d also love to see it–share your photo of this dish and tag me on Instagram and I’ll feature you! I appreciate you.

Looking for more Christmas morning breakfast ideas? Scroll below the recipe card and I’ll share some other favorites!

More Christmas Breakfast Ideas

Overnight Cranberry Cinnamon Rolls (pictured above) These are a little more work, but if you love cinnamon rolls, you’ve got to make these!

Cranberry Smoothie Want a lighter option for Christmas morning? This is perfect!

Triple Berry Baked Oatmeal–You can absolutely mix this together the night before and bake in the morning. Frozen berries work great when they aren’t in season!

Slow Cooker Cranberry Eggnog Oatmeal–It bakes in the slow cooker over night! Eggnog lovers will adore this one.

Orange Chocolate Chip Muffins–These are lovely and a perfect option for Christmas morning.

Overnight Christmas Breakfast Casserole Recipe