Name: overnight croissant breakfast casserole
Prep time: 15 min
Cook time: 45 min
Total time: 1 h
Cuisine: American
Ingredients: 5 large croissants (preferably day-old), torn into large chunks; 1 lb (450g) ground sausage, cooked and drained; 1 cup (120g) shredded cheddar cheese; 6 large eggs; 2 cups (475ml) whole milk; 1 teaspoon salt; ½ teaspoon black pepper; ½ teaspoon garlic powder; ½ teaspoon onion powder; Fresh parsley, chopped (optional, for garnish); Cooked turkey, chicken, or plant-based sausage; Swiss, Monterey Jack, or mozzarella cheese; Sautéed spinach, mushrooms, or bell peppers; Dash of hot sauce or red pepper flakes, for a spicy kick

This irresistible overnight croissant breakfast casserole is your new brunch secret weapon for 8 servings of pure comfort. Buttery croissant chunks, savory sausage, melty cheddar, and an ultra-creamy egg custard form cozy layers that soak up flavor all night long, so the oven does the heavy lifting in the morning. Whether you’re feeding a crowd or planning an indulgent weekend treat, this dish combines everyday ease with a special-occasion wow factor and delivers everyone’s favorite textures—crispy on top, custardy within—for 8 servings that vanish in record time.

Ingredients You’ll Need

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Ingredients You’ll Need

You only need a handful of simple, familiar ingredients to create a breakfast casserole packed with flavor and texture. Each element brings its own personality, from flaky croissants turning golden on the top, to hearty sausage and the magical melt of cheddar cheese.

Day-Old Croissants: About 5 large, torn into chunky pieces for extra luscious texture and buttery flavor throughout the casserole.
Ground Sausage (1 lb): A cooked and drained base adds a savory, meaty depth. Try spicy, mild, or even turkey or plant-based varieties.
Shredded Cheddar Cheese (1 cup): Delivers melty richness and that classic sharp zing—swap or mix with other cheese if you’re feeling creative.
Large Eggs (6): These bind everything together, creating a fluffy, protein-packed custard.
Whole Milk (2 cups): Lends creaminess and ensures your casserole is indulgently moist.
Salt (1 teaspoon): Brings all the savory notes to life.
Black Pepper (½ teaspoon): Adds just the right bite of warmth.
Garlic Powder (½ teaspoon): An extra layer of flavor, easy to incorporate without overwhelming.
Onion Powder (½ teaspoon): Effortlessly deepens the homemade vibe.
Fresh Parsley (optional, for garnish): A sprinkle of green at the end makes everything look fresh and inviting.
Optional Add-ins: Think cooked turkey, chicken, sautéed veggies, or a dash of hot sauce to make your 8 servings uniquely yours.

How to Make overnight croissant breakfast casserole

Step 1: Prepare the Base

Start by greasing a 9×13-inch baking dish—this ensures effortless serving and clean-up. Layer the torn croissants evenly across the bottom for that satisfying buttery foundation. Sprinkle cooked sausage evenly over the croissants, then shower everything with shredded cheddar cheese. This trio sets the stage for a casserole that feels both cozy and celebratory, and makes breakfast for 8 servings an event to look forward to.

Step 2: Make the Egg Mixture

Grab a large mixing bowl and whisk together your eggs, whole milk, salt, pepper, garlic powder, and onion powder until smooth and well blended. Carefully pour this savory custard all over the croissant and sausage layers, ensuring every nook soaks up the goodness. Gently press the croissants down with a spatula so everything gets a chance to absorb that eggy magic—this key move guarantees every bite is decadent yet never dry.

Step 3: Refrigerate Overnight

Once everything’s nestled in the dish and bathed in custard, cover tightly with foil. Let your casserole chill in the fridge for at least 6 hours, or overnight. This wait is absolutely worth it, as the croissants absorb every drop and the flavors meld together. Bonus: All the prep is done ahead, so you can sleep in knowing breakfast (or brunch for 8 servings) is nearly ready.

Step 4: Bake in the Morning

In the morning, preheat your oven to 350°F (175°C). Uncover the casserole, pop it in the oven, and bake for 40–45 minutes—until the top is golden and the center is set. Let it cool for about 10 minutes before slicing. This moment of patience rewards you with clean, satisfying slices perfect for serving up to 8 servings of croissant casserole magic.

How to Serve 8 servings

Garnishes

A generous sprinkle of fresh chopped parsley just before serving brings a pop of color and a little herbal brightness that balances all the rich flavors. You could also add a dusting of extra cheese, a hit of chili flakes, or even some chives for a twist. Don’t skip this final flourish—it really makes those 8 servings look irresistible.

Side Dishes

Pair your overnight croissant breakfast casserole with crisp fruit salad, roasted breakfast potatoes, or a refreshing citrus juice. A simple green salad can add a fresh, light contrast to the hearty, decadent casserole, rounding out an inviting meal for 8 servings that feels like a true brunch spread.

Creative Ways to Present

Try serving individual squares garnished with a dollop of sour cream, a drizzle of hot sauce, or even a little pesto for a flavor-packed finish. For a weekend brunch, stack slices alongside mimosa glasses or espresso cups. You can even dress up your 8 servings on a big platter with edible flowers or bundles of herbs for a bit of wow factor.

Make Ahead and Storage

Storing Leftovers

If you’re lucky enough to have leftovers after serving your 8 servings, let the casserole cool to room temperature, then transfer pieces to an airtight container. Store in the refrigerator for up to 4 days. The flavors only deepen as it sits, so those sneaky, next-day bites are extra special.

Freezing

This breakfast casserole is perfectly freezer-friendly, both before and after baking. For unbaked casserole, wrap tightly in foil and plastic wrap, then freeze for up to 2 months—just thaw overnight in the fridge before baking as usual. For baked leftovers, wrap well and freeze individual squares for an on-demand breakfast for one (or a second round for 8 servings down the road).

Reheating

To reheat, place slices on a baking sheet, cover lightly with foil, and warm in a 350°F oven for about 15 minutes, or until heated through. For a super-crispy top, uncover for the last 3 to 5 minutes. You can also microwave single portions for a quick, satisfying breakfast any day after your initial 8 servings feast.

FAQs

Can I use fresh croissants instead of day-old ones?

While you can use fresh croissants in a pinch, day-old ones are truly better. Their slightly firmer texture helps them absorb the creamy custard without becoming mushy, which keeps your casserole satisfyingly pillowy rather than soggy across all 8 servings.

What other meats can I use besides sausage?

Absolutely—try cooked bacon, diced ham, turkey sausage, or plant-based sausage. You can even combine a few for extra flavor. Just make sure any meat is cooked and drained before adding it to the croissant base so your 8 servings don’t end up greasy.

Does this casserole have to sit overnight?

Overnight resting is ideal because it lets the croissants really absorb the liquid and the flavors meld together, but if you’re crunched for time, you can chill for at least 6 hours. The longer the soak, the more cohesive and luscious your 8 servings will be.

Is it possible to make this gluten-free?

Yes! Swap the croissants for your favorite gluten-free equivalent or sturdy gluten-free bread. Double-check your sausage and other mix-ins to be sure they’re gluten-free as well, so everyone can enjoy all 8 servings without worry.

Can I add vegetables to the casserole?

Definitely! Sautéed mushrooms, spinach, diced bell peppers, or even kale make delicious add-ins. Make sure any vegetables are cooked and drained to avoid watering down your casserole. Adding veggies is a great way to pack more color and nutrition into your 8 servings.

Final Thoughts

If you’ve been searching for a brunch recipe that’s as fun to share as it is to make, this overnight croissant breakfast casserole is a winner every time. Whether you’re serving a crowd or just want leftovers for easy mornings, one batch delivers 8 servings of warm, cheesy comfort that’ll have everyone asking for seconds. Don’t be surprised when it becomes your most-requested dish—enjoy every bite!