Overnight Croissant Breakfast Bake

This overnight croissant breakfast casserole transforms buttery croissants into a decadent morning meal that requires minimal effort when you wake up. The combination of flaky pastry, savory sausage, and creamy egg custard creates a breakfast worthy of special occasions but simple enough for any weekend.

I first made this casserole when hosting family for the holidays, and it quickly became our traditional Christmas morning breakfast. The ability to prepare it the night before means I can focus on enjoying time with loved ones rather than cooking.

Ingredients

• Croissants: Large ones provide the perfect buttery base that creates a delightful texture between crispy and custardy
• Breakfast sausage: Adds savory flavor and protein, look for quality sausage with visible herbs and spices
• Cheddar cheese: Opt for freshly grated rather than pre-shredded for better melting and flavor
• Eggs: Use large eggs for consistent results and the richest custard
• Milk: Whole milk creates the creamiest result but 2% works well too
• Dry mustard: Provides subtle depth that enhances the savory elements
• Salt and pepper: Essential for bringing all the flavors together

Step-by-Step Instructions

Prepare the Baking Dish:

Thoroughly grease a 9×13 inch baking dish ensuring no spots are missed. Arrange the croissant pieces in an even layer allowing some pieces to overlap slightly. Using day-old croissants works best as they absorb more of the egg mixture without becoming overly soggy.

Layer the Protein and Cheese:

Distribute the cooked and crumbled breakfast sausage evenly over the croissant base making sure every serving will include some meat. Sprinkle the shredded cheese across the entire dish creating a blanket that will melt into golden perfection during baking.

Create the Custard:

Whisk eggs vigorously until completely uniform then gradually add the milk while continuing to whisk. Add the dry mustard, salt, and pepper ensuring they are fully incorporated with no clumps. The mustard might seem unusual but it adds a subtle complexity that elevates the entire dish.

Assemble and Soak:

Pour the egg mixture slowly over the entire casserole allowing it to seep between layers. Use a spatula to gently press down on the croissants ensuring they begin absorbing the custard. This step is crucial for texture development.

Overnight Rest:

Cover tightly with plastic wrap and refrigerate for at least 2 hours, though overnight yields the best results. This resting period allows the croissants to fully absorb the egg mixture and for flavors to meld together beautifully.

Baking Process:

Bring the casserole to room temperature as your oven preheats to ensure even cooking. Bake uncovered until the top develops a golden crust and the center is set but still slightly jiggly, about 40-45 minutes. The casserole will continue cooking slightly after removal.

Serving Method:

Allow the casserole to rest for 5-10 minutes after baking which helps the custard fully set for easier slicing. Cut into generous squares and serve while still warm for the most delightful texture contrast.

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The dry mustard in this recipe is my secret ingredient that most guests can never quite identify but always compliment. My grandmother taught me this trick years ago for egg dishes and I have never made a breakfast casserole without it since. The subtle tang it provides balances the richness perfectly.

Make It Your Own

This casserole welcomes creativity with open arms. Substitute the breakfast sausage with crispy bacon, ham, or make it vegetarian with sautéed mushrooms and spinach. The cheese can be swapped for gruyere, fontina, or a Mexican blend for different flavor profiles. You can also add vegetables like bell peppers, caramelized onions, or asparagus depending on what your family enjoys. Consider it a template rather than a strict recipe.

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Storage and Reheating

Leftovers keep beautifully in the refrigerator for up to 3 days. Cover individual portions with a damp paper towel before microwaving to prevent the croissants from becoming tough. For best results, reheat larger portions in a 325°F oven until warmed through, about 15 minutes. You can also freeze portioned leftovers for up to 2 months, wrap them tightly in plastic wrap then foil and thaw overnight in the refrigerator before reheating.

Serving Suggestions

This casserole pairs wonderfully with fresh fruit, a light green salad, or roasted tomatoes for balance. For brunch gatherings, serve alongside a simple yogurt parfait station and mimosas. During winter holidays, offer warm maple syrup on the side for guests who enjoy a sweeter breakfast experience. The dish is substantial enough to stand alone but versatile enough to complement other breakfast favorites.

Frequently Asked Questions

→ Can I use a different type of bread for this casserole?

Yes, you can substitute croissants with brioche, challah, or even day-old bread for a similar texture and flavor.

→ Can I make this dish gluten-free?

Absolutely! Use gluten-free bread or croissant alternatives to make the dish suitable for gluten-free diets.

→ Can I add vegetables to this casserole?

Yes, sautéed spinach, mushrooms, or bell peppers can be added for an extra layer of flavor and nutrition.

→ How far in advance can I prepare this dish?

You can prepare the casserole up to 24 hours in advance. Store it covered in the refrigerator and bake when ready.

→ Can I freeze leftovers?

Yes, you can freeze baked leftovers for up to three months. Reheat in the oven for best results.

→ What cheese works best for this dish?

Shredded cheddar is a classic choice, but you can use Swiss, Gouda, or a blend of your favorites.