This Overnight Croissant Breakfast Casserole brings all the comfort of a home-cooked morning meal with none of the morning chaos. Made with buttery croissants, savory sausage, and a rich, custardy egg mixture, it’s assembled the night before and baked fresh in the morning. Whether I’m feeding a house full of guests or just want to enjoy a slow Sunday morning, this casserole makes me feel like I’ve got breakfast handled before I even get out of bed.

Overnight Croissant Breakfast Casserole

Why You’ll Love This Recipe

I love how this casserole turns simple ingredients into something that feels indulgent, cozy, and completely satisfying. The prep is easy, and the flavor is deep and comforting. It tastes like something you’d expect from an old farmhouse breakfast, yet it fits effortlessly into a modern schedule.

I can prepare everything the night before and just pop it in the oven in the morning
It uses ingredients I often already have—no special trip to the store needed
The buttery croissants create a texture between French toast and bread pudding, making it rich and satisfying
It feeds a crowd—up to 12 portions from one baking dish
The sausage gravy takes it over the top and makes it unforgettable
It works well with gluten-free substitutions for those with dietary needs

Ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

Olive oil
Onion
Breakfast sausage
Large butter croissants
Shredded cheddar cheese
Large eggs
Heavy whipping cream
Whole milk
Dry mustard powder
Salt
Black pepper
Paprika
Garlic powder
Butter
All-purpose flour

Directions

I start by heating olive oil in a large skillet over medium heat. Once it shimmers, I add chopped onion and sauté until it’s soft and translucent—about 3 to 4 minutes.
I add the breakfast sausage and cook it until browned, breaking it up as it cooks. I drain the fat but save about 2 tablespoons for the gravy.
I let the sausage mixture cool for 10–15 minutes. This step is key—if it’s too hot, it could cook the eggs too early when everything is combined.
While the sausage cools, I tear the croissants into 2-inch pieces and toss them in a large bowl with the cooled sausage and shredded cheddar cheese.
I transfer everything into a greased 9×13-inch baking dish, spreading it evenly so every bite has a bit of everything.
In a separate bowl, I whisk together the eggs, heavy cream, ½ cup of the milk, dry mustard, salt, pepper, paprika, and garlic powder until fully combined.
I pour this egg mixture over the croissants, pressing down gently to help it absorb. Then I cover the dish tightly and refrigerate overnight (or at least 8 hours).
The next morning, I preheat the oven to 350°F and bake the casserole uncovered for 35–45 minutes. It’s ready when the top is golden and the center no longer jiggles.
While it bakes, I make the sausage gravy. I melt butter with the reserved sausage fat, whisk in the flour, and cook for a minute before gradually adding the remaining 2½ cups milk. I stir constantly until it thickens, seasoning to taste with salt and pepper.
I let the casserole rest for 10 minutes before slicing and serve it with the warm gravy on the side.

Servings And Timing

This recipe makes 12 hearty servings.

Prep Time: 30 minutes
Refrigeration Time: 8 hours (or overnight)
Cook Time: 40 minutes
Total Time: 1 hour 10 minutes

Variations

Gluten-Free: I use gluten-free croissants and a 1:1 gluten-free flour blend for the gravy
Vegetarian: I replace the sausage with sautéed mushrooms, spinach, or a meatless sausage alternative
Cheese Options: Sometimes I swap the cheddar for Gruyère, Monterey Jack, or pepper jack for a little kick
Spicy Version: I use hot sausage and add a pinch of red pepper flakes to the egg mixture
Make It Sweeter: If I’m craving something less savory, I leave out the sausage and cheese, and add berries or baked apples with a sprinkle of cinnamon sugar

Storage/Reheating

I store leftovers in an airtight container in the fridge for up to 3 days. To reheat, I place a portion on a plate, cover it with a damp paper towel, and microwave for 60–90 seconds. For a crisper top, I reheat it in a 300°F oven for about 10 minutes.

The sausage gravy also keeps well in the fridge. I reheat it on the stovetop with a splash of milk or in the microwave, stirring every 30 seconds until warm.

If I want to freeze it, I bake the casserole first, let it cool completely, then portion and freeze it for up to 2 months. I reheat frozen pieces in the oven for the best texture.

FAQs

Can I Use Regular Bread Instead Of Croissants?

I’ve tried using brioche and challah in a pinch, and both work well, but I always come back to croissants for that buttery, indulgent texture.

How Do I Prevent The Casserole From Becoming Soggy?

I let the sausage mixture cool completely before mixing and tear the croissants into larger pieces so they soak up the custard without falling apart.

Can I Make This Casserole Gluten-Free?

Yes, I’ve had success using gluten-free croissants and a gluten-free flour blend for the gravy. Just make sure your sausage and seasonings are gluten-free as well.

Can I Freeze This Casserole Before Baking?

I don’t recommend freezing it before baking because the texture changes. Instead, I bake it first, let it cool, and freeze portions for easy reheating.

What If I Don’t Have Heavy Cream?

Half-and-half works well in place of heavy cream, though the result is slightly less rich. I avoid using only milk since it makes the casserole less custardy.

Conclusion

This Overnight Croissant Breakfast Casserole is the kind of recipe I turn to when I want something easy, cozy, and guaranteed to impress. It saves me time in the morning and fills the kitchen with the kind of comforting aroma that brings people together. Whether it’s for a holiday brunch or just a quiet weekend at home, this dish never fails to deliver.