If you’re on the hunt for a dish that brings comfort, flavor, and wow-factor to any breakfast table, look no further than this Overnight Croissant Breakfast Bake. With rich, buttery croissants as the base, savory sausage, tender spinach, a kiss of onion, and a custardy egg layer, this casserole celebrates the best of breakfast in every forkful. The best part? Most of the work is done the night before, so you can wake up feeling like a breakfast hero with minimal effort. Whether you’re feeding a brunch crowd, treating your family, or just want leftovers to savor all week, this is a recipe you’ll find yourself craving again and again.

Overnight Croissant Breakfast Bake Recipe - Recipe Image

Ingredients You’ll Need

Don’t be put off by the ingredient list; every item here plays an essential role and comes together effortlessly. The magic of this Overnight Croissant Breakfast Bake is that each component adds depth, texture, and color, creating a dish that’s both impressive and incredibly easy to pull off.

Croissants (4-6 large, day old are best): Their flaky, buttery richness soaks up the custard and delivers irresistible texture.
Italian or spicy sausage (1 pound): Adds a punch of flavor and a satisfying, hearty bite—feel free to use more if you love extra protein.
Onions (2 cups, chopped): These caramelize slightly as they bake, giving sweetness and aromatic depth.
Olive oil or butter (1 tablespoon): Used for sautéing, lends flavor and helps soften the veggies to perfection.
Fresh spinach (2 cups): Sneaks in a pop of color and a nutritional boost without overwhelming the dish.
Grated cheese (2 cups cheddar, Monterey Jack, Pepper Jack, mozzarella, or your favorite combo): Melts into gooey, golden bliss for that classic breakfast casserole finish.
Eggs (12 large): The star of the show, binding everything into a tender, custardy bake.
Half and half (1 1/2 cups): Rich and creamy, this ensures the casserole is lovely and luscious instead of dry.
Dry mustard (1 teaspoon): Boosts savoriness and adds a subtle tang that perks up everything.
Salt (1 teaspoon): Brings all the flavors together harmoniously.
Ground pepper (1 teaspoon): For just the right touch of heat and depth.

How to Make Overnight Croissant Breakfast Bake

Step 1: Prep the Pan

Start by greasing a 9×13-inch (or larger) casserole dish. This is crucial to prevent sticking and ensures that every slice comes out clean and beautiful for serving. If you want a golden, slightly crisp edge, don’t be shy with the butter or cooking spray.

Step 2: Build Your Croissant Base

Tear your croissants into large, rustic chunks and lay them evenly in your greased casserole dish. The more uneven and craggy, the better—they’ll soak up the egg custard and reward you with pockets of softness and crunch.

Step 3: Cook and Drain the Sausage

Brown the sausage in a large pan until fully cooked and a bit crispy on the edges. Once done, transfer the sausage to a plate lined with paper towels. Pat away any extra grease—you want the flavor, but not excess oil in your breakfast bake.

Step 4: Layer the Sausage

Evenly distribute your drained sausage on top of the croissant base. This ensures every bite has a delicious hit of savory sausage alongside that flaky pastry.

Step 5: Sauté Vegetables

Wipe the pan to remove extra grease, then cook the onions in a bit of olive oil or butter until soft and fragrant—about five minutes. Stir in the fresh spinach and cook just until wilted. Pour this mixture right over the sausage, and finish with a generous layer of your chosen cheeses.

Step 6: Make the Custard

In your blender or a large mixing bowl, combine the eggs and half-and-half. Whisk or blend until smooth, then season with dry mustard, salt, and pepper. This seasoned custard is poured slowly over your beautifully filled casserole dish, making sure to saturate every nook and cranny.

Step 7: Cover and Chill Overnight

To keep your cheese from sticking, spray your foil with cooking spray before covering the dish—sprayed side down. Tuck your casserole into the fridge overnight and let the croissants soak up all those flavors.

Step 8: Bring to Room Temperature

The next morning, remove your Overnight Croissant Breakfast Bake from the refrigerator 30-60 minutes before baking. This takes the chill off, ensuring even cooking and the perfect, creamy texture.

Step 9: Preheat Your Oven

Set your oven to 375 degrees Fahrenheit and adjust a rack to the center position. This ensures your casserole bakes evenly, getting golden and puffed on top while setting beautifully inside.

Step 10: Bake

Bake your casserole, still covered with foil, for 30 minutes. Then, carefully remove the foil and bake for another 30 minutes or until the top is slightly puffed and the eggs are set in the center. The aroma will have everyone circling the kitchen!

Step 11: Rest and Serve

Once baked, remove from the oven and cool for about 30 minutes. This rest time lets the casserole set, making it easier to slice into neat, generous squares. Serve with a drizzle of chili sauce or a side of your favorite salsa for a lively finish.

How to Serve Overnight Croissant Breakfast Bake

Garnishes

Give your Overnight Croissant Breakfast Bake extra flair by topping each serving with a sprinkle of fresh herbs like chopped chives, parsley, or a little dill. A spoonful of creamy sour cream, a scatter of sliced green onions, or even a dusting of smoked paprika can transform each piece into a gourmet delight.

Side Dishes

This casserole pairs wonderfully with simple sides. Serve it alongside a bright, crisp fruit salad to balance out the richness, or roast some breakfast potatoes if you want an even heartier meal. Fresh mixed greens tossed in a light vinaigrette are also a lovely, refreshing contrast.

Creative Ways to Present

For an elegant brunch table, cut the Overnight Croissant Breakfast Bake into smaller squares and arrange them on a platter with garnishes on the side. For a more casual vibe, serve straight from the baking dish, letting everyone dig in family-style. You can even bake in individual ramekins for cute, personalized portions at a special gathering.

Make Ahead and Storage

Storing Leftovers

Leftover Overnight Croissant Breakfast Bake keeps well in an airtight container in the refrigerator for up to four days. Allow it to cool completely before storing to preserve its texture, and don’t forget to label the container with the date!

Freezing

This breakfast bake is freezer-friendly. After it has cooled, cut into individual portions, wrap snugly in foil or plastic wrap, and store in a freezer-safe bag or container for up to two months. Thaw overnight in the fridge before reheating.

Reheating

To reheat, simply warm portions in a 350 degree oven (covered lightly with foil) until heated through, about 10-15 minutes. Microwaving also works in a pinch, though the oven method keeps the top nice and crisp.

FAQs

Can I make the Overnight Croissant Breakfast Bake vegetarian?

Absolutely! Substitute the sausage with a plant-based sausage or sautéed mushrooms and extra veggies. You’ll still get tons of flavor and a satisfying, hearty breakfast without the meat.

What if I don’t have day-old croissants?

Fresh croissants work just fine. For the best texture, you can quickly toast them in a low oven (300 degrees for about 10 minutes) to dry them out a bit before assembling the casserole.

Can I use a different type of bread?

Yes! While croissants are the star for their buttery flakiness, brioche or challah would be delicious alternatives, though the flavor and texture will be slightly different.

Do I have to let it sit overnight?

Allowing the bake to rest overnight results in the best flavor and texture, but if you’re pressed for time, let it soak for at least 2-3 hours before baking to ensure the custard absorbs into the bread fully.

What’s the best way to serve this for a brunch party?

Serve it buffet-style with toppings on the side so guests can customize to their liking, or cut into bite-sized squares and offer with toothpicks for an easy, portable option at gatherings.

Final Thoughts

Don’t wait for a special occasion to enjoy the magic of Overnight Croissant Breakfast Bake! It’s cozy, convenient, and guaranteed to impress anyone lucky enough to try it. Gather your ingredients, give it a try, and watch this become a beloved staple at your breakfast table.