Overnight Croissant Breakfast Casserole Recipe

If you’re looking for a brunch showstopper with minimal morning effort, let me introduce you to the Overnight Croissant Breakfast Casserole. Pillowy croissants, hearty sausage, gooey cheese and a rich, custardy base meld together overnight and bake up golden and heavenly. This is the kind of recipe that makes you feel like you’ve stumbled onto a secret café breakfast—except it’s made in your own kitchen, with everything prepped the night before. One bite and you’ll see why it’s destined to become your new comfort food tradition!

Ingredients You’ll Need

Every component in this Overnight Croissant Breakfast Casserole plays a special role: from savory sausage to the buttery croissants that soak up all the luscious flavors. Don’t be intimidated by the list–each item is straightforward and chosen for its ability to add amazing texture, color, or richness. Let’s take a closer look:

• Olive oil: A touch of olive oil softens the onions and helps the sausage brown beautifully.
• Onion (small, peeled and chopped): Adds depth, sweetness, and the cozy aroma that makes this casserole so irresistible.
• Breakfast sausage (1 lb, mild): Brings that classic breakfast flavor—choose mild for crowd-pleasing comfort, or use spicy if you love a kick!
• Butter croissants (4 large or 8 small): Buttery, flaky croissants create the ultimate base, soaking up the tasty egg custard without getting soggy.
• Shredded cheddar cheese (1 cup): Melts into the casserole, giving each bite a little gooey, tangy goodness.
• Eggs (6 large): These hold everything together and make the base ultra-creamy.
• Heavy whipping cream (1/2 cup): For extra richness and an indulgently velvety custard.
• Whole milk (3 cups, divided): Adds lightness to the custard and is the key to a silky homemade gravy.
• Dry mustard powder (1/2 tsp): Offers subtle sharpness and enhances the overall flavor.
• Salt (1/2 tsp, plus to taste): Boosts and balances every savory bite and seasons the gravy just right.
• Black pepper (1/2 tsp, plus extra for gravy): A must for seasoning both the casserole and the creamy topping.
• Paprika (1/4 tsp): Lends a gentle warmth and lovely color without overpowering spice.
• Garlic powder (1/4 tsp): Rounds out the flavors with a mellow, savory background.
• Butter (2 tbsp): Combines with sausage drippings for a gravy that’s rich and glossy.
• All-purpose flour (3 tbsp): Thickens the gravy to the perfect, pourable texture.

How to Make Overnight Croissant Breakfast Casserole

Step 1: Sauté the Aromatics and Sausage

Start by heating up the olive oil in a large skillet over medium heat. Toss in your chopped onion and let it sizzle until it turns soft and translucent, filling your kitchen with mouthwatering aromas. This is the moment where flavor really begins! Add the breakfast sausage next, breaking it into crumbles as it browns. Be patient and let it get caramelized in spots—it makes all the difference. Don’t forget to save some of the rendered fat for your gravy later, then drain the rest and let the mixture cool slightly.

Step 2: Prepare Croissants and Layer the Casserole

Tear the croissants into chunky, rustic pieces and place them in a mixing bowl. Pour the cooled sausage and onion mixture right on top, then add your shredded cheddar. Toss everything together until the croissants are happily tumbled with sausage and cheese. Gently spread this dreamy mixture into a greased 9×13-inch baking dish, nudging everything into an even layer so every bite gets a bit of each component.

Step 3: Make the Egg Custard

In a separate bowl, whisk up the eggs, heavy cream, half a cup of milk, and all the dry seasonings: mustard powder, salt, pepper, paprika, and garlic powder. This is where you’re building the luscious, savory custard that transforms the casserole into something extraordinary. Pour it evenly over the croissant mix in your baking dish, making sure everything’s well-coated. Cover tightly with a lid or plastic wrap, and slide it into the refrigerator for the night—this is when the flavors meld and soak in!

Step 4: Bake Until Golden

Come morning, preheat your oven to 350°F (175°C). Remove the casserole from the fridge and let it stand while the oven heats, which will help it bake evenly. Pop it in the oven and let it bake for 35 to 45 minutes. You’re looking for a puffed, golden top with irresistibly melted cheese. A little patience pays off big here—the aroma alone will have everyone running to the kitchen.

Step 5: Whip Up Creamy Gravy

While the casserole bakes, start the homemade gravy as the ultimate finishing touch. Melt butter in a saucepan and add the reserved sausage drippings for a depth of flavor you just can’t fake. Sprinkle in flour and stir constantly for a minute to make a roux, then gradually whisk in the remaining 2 ½ cups of milk. Keep stirring as it thickens to a creamy, pourable consistency. Season with extra salt and pepper to your liking—you want a gravy that perfectly complements the richness of the Overnight Croissant Breakfast Casserole.

Step 6: Serve and Savor

Once your casserole is gloriously puffed and golden, take it out of the oven and let it rest briefly. Serve it warm, spooned onto plates and topped or sided with a generous ladle of your homemade gravy. All that’s left is to grab a fork and dive in!

How to Serve Overnight Croissant Breakfast Casserole

Garnishes

This dish is already a looker, but a sprinkle of freshly chopped herbs adds a pop of color and freshness that brightens every bite. Try a handful of chives, parsley, or even thinly sliced green onions right before serving for that final flourish your Overnight Croissant Breakfast Casserole deserves.

Side Dishes

A crisp green salad tossed in a zippy vinaigrette is the perfect counterbalance to all the comfort in this casserole. Fresh fruit salad, citrus wedges, or even roasted asparagus bring brightness and make your breakfast spread feel extra-special for guests or family weekends.

Creative Ways to Present

To elevate presentation, consider baking the Overnight Croissant Breakfast Casserole in individual ramekins for brunch parties, or cut it into neat squares for easy serving on a buffet. Serve with mini pitchers of gravy on the side—or even top with a soft-cooked egg for an extra indulgent brunch plate!

Make Ahead and Storage

Storing Leftovers

If you somehow have leftovers, store them in an airtight container in the refrigerator for up to three days. The flavors continue to mingle, and reheated portions taste just as cozy and delicious as fresh!

Freezing

The Overnight Croissant Breakfast Casserole freezes beautifully. Wrap the cooled casserole (either whole or cut into portions) tightly in plastic wrap and foil, then tuck it in the freezer for up to two months. Just thaw overnight in the fridge before reheating for best texture.

Reheating

Warm leftover casserole in the oven at 350°F until heated through and bubbly, or use the microwave for individual slices. Reheat the gravy separately over low heat, stirring in a bit of milk if it’s too thick, and pour or drizzle over just before serving.

FAQs

Can I make Overnight Croissant Breakfast Casserole vegetarian?

Yes! Simply swap the breakfast sausage for your favorite plant-based sausage or add hearty sautéed mushrooms and spinach for plenty of savory, meaty flavor minus the meat.

Can I use store-bought mini croissants?

Absolutely—store-bought croissants (either large or small) work great. Mini ones add extra texture and little pockets of croissant-y goodness in every bite!

What cheese varieties can I substitute for cheddar?

Try Monterey Jack, Swiss, Gruyère, or a Mexican cheese blend for fun flavor variations. Just make sure it’s a good melting cheese for gooey results.

How far ahead can I assemble the casserole?

You can prep Overnight Croissant Breakfast Casserole up to 24 hours in advance, making it perfect for stress-free entertaining or an easy weekend treat.

Is it possible to skip the gravy?

Of course—the casserole is incredible on its own. The gravy just takes it over the top, so feel free to skip or swap for a lighter sauce, hot sauce, or even a dollop of crème fraîche.

Final Thoughts

There’s something almost magical about this Overnight Croissant Breakfast Casserole. It’s easy enough for any morning but special enough for guests, holidays, or even just treating yourself. Give it a try—you might just discover your new favorite breakfast comfort classic!

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