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Looking for a show-stopping breakfast casserole that practically cooks itself overnight? You’ve landed in the right spot. I first tried this Overnight Croissant Breakfast Casserole on a chaotic Saturday morning when my oven and I had zero plans to cooperate. Spoiler: it came out golden, fluffy, and utterly delicious. I’ll walk you through my favorite Breakfast Casserole Make Ahead hack, sprinkle in some Savory Breakfast tips, and share why this recipe beats every Brunch Casserole I’ve ever made.
Ever wondered why croissants? They soak up custard like pros, turning every bite into a buttery, custardy cloud. This recipe ranks top among my Breakfast Casserole Recipes and doubles as one of those Easy Breakfast Ideas you mention when someone yells “I’m starving!” around the dinner table. IMO, it’s even better than that classic Overnight Breakfast Casserole With Hashbrowns—and FYI, I LOVE hashbrowns. 😉
Whether you need Breakfast Ideas For A Crowd at a Brunch Potluck or just a cozy dish to impress your roommates on Sunday, stick around. I promise this is the most fuss-free, make-ahead, slightly over-the-top recipe you’ll bookmark this year.
Ingredients
- 6 large croissants, torn into bite-sized pieces
- 8 large eggs
- 2 cups whole milk (or half-and-half for extra creaminess)
- 1 cup shredded cheddar cheese
- 1 cup shredded Gruyère cheese
- 1 cup diced ham (or cooked bacon/pancetta)
- 1 small onion, finely chopped
- 2 cloves garlic, minced
- 1 tbsp Dijon mustard
- 1 tsp dried thyme
- Salt and freshly ground black pepper, to taste
- 2 tbsp butter, melted (for greasing the pan)
Instructions
- Grease a 9×13-inch baking dish with melted butter.
- Toss the torn croissant pieces evenly into the dish.
- In a large bowl, whisk eggs, milk, Dijon mustard, thyme, salt, and pepper until smooth.
- Sauté onion and garlic in a small pan over medium heat until translucent (about 3 minutes).
- Stir the sautéed onion and garlic into the egg mixture.
- Layer diced ham evenly over the croissants, then pour the egg mixture on top.
- Sprinkle the shredded cheddar and Gruyère cheeses over everything.
- Cover the dish tightly with plastic wrap. Refrigerate overnight for best results.
- Preheat your oven to 350°F (175°C). Remove the plastic wrap and let the dish sit at room temperature for 15 minutes.
- Bake uncovered for 35–40 minutes until the top turns golden brown and the center sets (insert a knife; it should come out mostly clean).
- Let the casserole rest for 5–10 minutes before slicing. This “rest” is key for neat squares—and fewer oozy disasters.
Variations
Feel like mixing it up? Here are three fun spins on this breakfast casserole favorite:
- Veggie & Feta Twist: Swap ham for sautéed spinach, bell peppers, and mushrooms. Crumble in ½ cup of feta for a tangy punch—perfect for your next Egg Frittata craving.
- Spicy Chorizo Edition: Replace ham with crumbled chorizo or spicy Italian sausage. Add chopped jalapeños and a sprinkle of smoked paprika. This one’s a bold Breakfast Ideas Casserole winner.
- Sweet Breakfast Basket: Turn dessert into breakfast. Use mini croissants, add cinnamon, nutmeg, and swap cheeses for mascarpone. Drizzle with maple syrup just before serving.
Serving & Tips
Serve this casserole as the centerpiece of any brunch spread. It pairs amazingly with fresh fruit, a side of mixed greens, or a fruit-packed Breakfast Basket. Feeling extra? Top each slice with avocado, a dollop of sour cream, or even a spoonful of salsa.
Storage Tips:
- Store leftover slices in an airtight container: they’ll stay fresh in the fridge up to 4 days.
- Reheat gently in a 325°F oven for 10 minutes or microwave on 50% power for 1–2 minutes.
- Want to freeze? Wrap individual slices in foil, then place in a freezer bag. They’ll keep for up to 2 months.
Seasonal Touch: This casserole shines in cooler months. Add a pinch of nutmeg and swap thyme for fresh rosemary to give it that cozy, holiday‐ready vibe. You’ll feel like you just walked into your grandma’s kitchen—minus the guilt of stealing her secret recipe.
Final Thoughts
I still smile about the first time I served this to my skeptical friends. They expected dry bread pudding but got buttery, custardy bliss instead. No one believed I’d whipped it together before bed! Whether you’re prepping for Brunch Potluck fame or simply craving a make-ahead dish that feels fancy (but really isn’t), this Overnight Croissant Breakfast Casserole has your back. It combines the ease of Easy Breakfast Casserole With Hashbrowns vibes with the elegance of a Tortilla Quiche Bake. Trust me, even your most carb-conscious friend will sneak a second helping. 🙂
Overnight Croissant Breakfast Casserole
Ingredients
Equipment
Method
- Grease a 9×13-inch baking dish with non-stick spray or butter. Scatter the torn croissant pieces evenly across the dish.
- In a large bowl, whisk together the eggs, milk, salt, pepper, thyme, and garlic until smooth. Pour this custardy mixture over the croissants, pressing down lightly so they soak it up.
- Sprinkle the diced ham (or bacon), chopped onion, and optional spinach over the croissants. Top with both cheeses, distributing evenly.
- Cover the dish tightly with plastic wrap and refrigerate for at least 6 hours, preferably overnight.
- Preheat the oven to 350°F (175°C) one hour before serving. Remove plastic wrap and bake for 40–45 minutes, or until the top turns golden brown and the center jiggles just slightly.
- Let it rest for 5 minutes before slicing. Serve hot, garnish with fresh parsley or chives if desired.
Nutrition
Notes
Tried this recipe?
Let us know how it was!FAQs
Can I prep this casserole less than overnight?
Yes! If you’re in a rush, let it soak at least 2 hours in the fridge. It won’t be as custardy, but it still tastes great—just call it “Quick Croissant Bake.”
What’s the best cheese swap?
You can’t go wrong with a blend of Swiss and mozzarella for a milder flavor. If you crave zing, add pepper jack or swap in goat cheese for creaminess.
Can I make this gluten-free?
Absolutely. Use gluten-free croissants or thick slices of your favorite GF bread. The custard soaks up just as well—you won’t miss the gluten.
How do I adapt this for a vegetarian crowd?
Skip the ham and load up on sautéed vegetables like zucchini, broccoli florets, or roasted red peppers. Stir in fresh herbs (basil, oregano) for an extra flavor punch.
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