If you’re looking for a cozy, make-ahead breakfast that feels a little fancy but is totally fuss-free, you’re going to adore this Croissant Breakfast Bake with Mushrooms and Spinach Recipe. It’s one of those dishes I turn to when I want something comforting yet impressive, especially on a weekend morning when the whole family wants a slow, relaxed start. Toasty croissants soaked in a rich custard, paired with earthy mushrooms and fresh spinach, all baked to cheesy perfection—trust me, once you make it, it might just become your new favorite brunch staple.
Why You’ll Love This Recipe
- Make-Ahead Ease: Prep it the night before and wake up to a nearly ready-to-bake breakfast.
- Luxury with Comfort: Buttery croissants meet earthy mushrooms and melty gruyere for a deliciously indulgent morning.
- Versatile Flavors: You can easily tweak veggies or cheeses to suit your taste or what you have on hand.
- Family Friendly: My crew goes wild for it, and it’s perfect for feeding a crowd without stress.
Ingredients You’ll Need
Choosing fresh, quality ingredients here really brings this Croissant Breakfast Bake with Mushrooms and Spinach Recipe to life. The croissants provide buttery richness, while the mushrooms and spinach add a fresh, earthy balance. Don’t skip the gruyere—its nutty flavor makes the whole dish sing.
- Croissants: Go for day-old or slightly stale if you can; they’ll soak up the custard better without turning soggy.
- Unsalted butter: Perfect for sautéing and greasing to control salt in the dish.
- Sweet onion: Adds a subtle sweetness that pairs amazingly with mushrooms.
- Garlic cloves: Minced for that subtle aromatic punch.
- Cremini mushrooms: Earthy and meaty, but you can swap with button mushrooms if needed.
- Fresh baby spinach: Wilts beautifully and adds a fresh green pop.
- Kosher salt and pepper: Essential for seasoning every layer well.
- Large eggs: The custard base that holds it all together.
- Milk: Adds creaminess without heaviness.
- Heavy cream: For that luscious custard texture.
- Gruyere cheese: Freshly grated melts beautifully and brings a nutty richness.
- Fresh chopped parsley: For topping and a fresh finish.
- Parmesan cheese: Adds a sharp finish on top before serving.
Variations
I’ve played around with this Croissant Breakfast Bake with Mushrooms and Spinach Recipe quite a bit, tweaking ingredients based on what’s in my fridge or the season. Feel free to make it your own!
- Cheese swaps: Sometimes I use sharp cheddar or fontina instead of gruyere, and it’s still fantastic.
- Veggie variations: Adding sautéed bell peppers or swapping spinach for kale gives it a fun twist.
- Protein additions: Crumbled breakfast sausage or crispy bacon make it heartier, perfect for weekend brunches.
- Dairy-free option: Try coconut milk and nutritional yeast for a vegan-friendly version that’s surprisingly tasty.
How to Make Croissant Breakfast Bake with Mushrooms and Spinach Recipe
Step 1: Toast the croissants toasty perfection
Start by preheating your oven to 450°F. Place your croissants cut-side up on a baking sheet and toast them for about 5 to 8 minutes until they’re golden and a little crisp on the edges. This step might seem small, but I learned this trick early on—it helps the croissants hold up when soaked in the custard instead of turning into mush. Let them cool just enough to handle, then chop or tear into bite-sized pieces.
Step 2: Sauté the veggies for deep flavor
While the croissants are toasting, melt the butter in a skillet over medium-low heat. Toss in the diced sweet onion and garlic, letting them soften slowly for about 5 minutes—this gentle cooking brings out a sweet aroma without burning. Next, add the chopped mushrooms, cooking for about 5 more minutes until they’re juicy and reduced. Then stir in the fresh baby spinach just until it wilts. Season everything with a big pinch of kosher salt and freshly cracked pepper. I love this step because it builds the flavorful base that’ll infuse the whole bake.
Step 3: Combine croissants and veggies in a buttered dish
Grab a 9×13-inch baking dish and brush it with melted butter to prevent sticking and add richness. Toss your toasted croissant pieces together with the mushroom-spinach mixture until evenly combined. This mix is already smelling amazing, isn’t it?
Step 4: Whisk the custard and mix in cheese
In a large bowl, whisk together the eggs, milk, heavy cream, and seasoning with salt and pepper. This custard mixture is what transforms the whole bake into a tender, custardy delight. Stir in about a cup of freshly grated gruyere cheese for richness—and if you’re anything like me, toss in a handful of fresh herbs like parsley or chives for a fresh burst of flavor (totally optional, but totally yum!). Set the rest of the cheese aside for topping later.
Step 5: Soak, chill, then bake
Pour the egg and cheese custard over the croissant and veggie mixture in your baking dish. Use your hands or a spatula to press the croissants down gently into the custard so they soak it all up. Cover the dish tightly with plastic wrap and pop it in the fridge for at least 8 hours, or overnight. This is the magic behind this recipe—it gives time for the croissants to absorb all that custardy goodness. When you’re ready to bake, preheat your oven to 350°F and take the dish out about 30 minutes beforehand to bring it to room temperature. Then, remove the plastic wrap, sprinkle the remaining gruyere on top, and bake uncovered for about 45 minutes until golden and set. Before serving, add a sprinkle of parmesan cheese and fresh parsley for a beautiful finishing touch.
Pro Tips for Making Croissant Breakfast Bake with Mushrooms and Spinach Recipe
- Croissant Choice Matters: I learned that using day-old croissants helps them soak up the custard without getting too soggy—fresh ones work but can get mushy quickly.
- Low and Slow Sauté: Cooking onions and mushrooms slowly develops deep flavors—you don’t want to rush this step, trust me!
- Don’t Skip Resting: Letting the dish come to room temperature before baking prevents uneven cooking and helps it set perfectly.
- Cover Tight, Chill Deep: Wrapping the dish tightly ensures the croissants soak the custard overnight, which makes all the difference in texture.
How to Serve Croissant Breakfast Bake with Mushrooms and Spinach Recipe
Garnishes
I love finishing this bake with a sprinkle of bright fresh parsley and a little extra grated parmesan to add some sharpness and color contrast. You could also scatter some thinly sliced green onions or a few chili flakes if you want a subtle kick. These garnishes really elevate the dish from cozy comfort to brunch-worthy.
Side Dishes
Pairing this bake with simple roasted tomatoes or a crisp mixed greens salad really balances the richness. My family often enjoys it alongside fresh fruit or even a lightly dressed arugula salad for a peppery bite that complements the creamy custard.
Creative Ways to Present
For special occasions, I like to scoop the bake into individual ramekins before baking for a personalized touch—the presentation is so charming and guests love it. You could also add some edible flowers or microgreens on top for a fancy brunch table moment.
Make Ahead and Storage
Storing Leftovers
I store leftovers covered tightly in the fridge and they keep well for up to 3 days. The flavors actually deepen after a day, making reheated slices just as good (if not better) than fresh out of the oven.
Freezing
While I haven’t frozen the full bake successfully (the croissants get a bit tough), I do freeze individual slices wrapped well in plastic and foil for up to a month. Thaw overnight in the fridge for best results.
Reheating
To reheat, I pop slices in a 350°F oven for 10-15 minutes until warm and the edges regain some crispness. Microwave works too in a pinch, but it can make the croissants a little soft.
FAQs
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Can I use frozen croissants for the Croissant Breakfast Bake with Mushrooms and Spinach Recipe?
You absolutely can! Just thaw them fully and toast lightly before assembling so they don’t turn soggy. Using slightly stale or day-old croissants usually gives the best custard absorption, but thawed frozen croissants work well when toasted first.
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Is it necessary to refrigerate the bake overnight?
Yes, refrigerating overnight is key. It allows the croissants to soak up the egg custard fully, resulting in a creamy, tender texture when baked. If you’re short on time, a few hours can work but overnight yields the best results.
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Can I prepare this bake gluten-free?
This recipe relies on croissants for its flaky texture, which are not gluten-free. However, you could experiment with gluten-free bread or rolls toasted the same way, though the texture and flavor will differ somewhat.
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What cheese substitutes work well?
Gruyere is ideal for its melt and flavor, but Emmental, fontina, or even sharp cheddar can work in a pinch. Avoid watery cheeses like fresh mozzarella, which can add excess moisture.
Final Thoughts
This Croissant Breakfast Bake with Mushrooms and Spinach Recipe has become one of those dishes I’m always happy to share because it feels like a treat and comfort food all at once. Its ease, flavor, and the way it fills the kitchen with a heavenly aroma make it a must-have in my brunch rotation. Give it a shot—I promise, you’ll love waking up to a breakfast that’s both effortless and so delicious. And hey, sharing it with friends or family means you get to enjoy the compliments too!
Print
Croissant Breakfast Bake with Mushrooms and Spinach Recipe
- Prep Time: 45 minutes
- Cook Time: 45 minutes
- Total Time: 8 hours 30 minutes
- Yield: 8 servings
- Category: Breakfast Casserole
- Method: Baking
- Cuisine: American
Description
A delicious and hearty overnight croissant breakfast bake featuring toasted buttery croissants, sautéed mushrooms, spinach, and a creamy egg mixture baked with melted Gruyere cheese. Perfect for a make-ahead breakfast or brunch, this dish combines savory flavors with a custardy texture that’s sure to please a crowd.
Ingredients
Croissants
- 5 to 7 large croissants, sliced in half lengthwise
- 2 tablespoons unsalted butter (for sautéing and greasing)
Vegetables & Herbs
- 1 sweet onion, diced
- 2 garlic cloves, minced
- 10 ounces cremini mushrooms, chopped
- 8 ounces fresh baby spinach
- Fresh chopped parsley, for topping
Egg Mixture
- 8 large eggs
- 2 ½ cups milk
- 1 cup heavy cream
- Kosher salt and pepper, to taste
- Handful of fresh chopped herbs (parsley, chives) – optional
Cheese
- 8 ounces Gruyere cheese, freshly grated
- Parmesan cheese, for topping
Instructions
- Toast Croissants: Preheat the oven to 450°F. Place the croissants cut-side up on a baking sheet and bake for 5 to 8 minutes until they are toasty. Remove from the oven and allow them to cool slightly before chopping or tearing into pieces.
- Sauté Vegetables: Heat the butter in a large skillet over medium-low heat. Add the diced onions and minced garlic and cook for about 5 minutes until softened. Stir in the chopped mushrooms and cook another 5 minutes until they are plump and juicy. Add the spinach and stir until it wilts. Season with kosher salt and pepper and mix well.
- Prepare Baking Dish: Brush a 9×13-inch baking dish with melted butter. Combine the toasted croissant pieces with the sautéed vegetable mixture in the dish and toss well to combine everything evenly.
- Make Egg Mixture: In a large bowl, whisk together the eggs, milk, heavy cream, and a generous pinch of salt and pepper. Stir in 1 cup of the grated Gruyere cheese and, if desired, a handful of fresh chopped herbs like parsley and chives for added flavor.
- Combine and Soak: Pour the egg mixture over the croissant and vegetable mixture in the baking dish. Gently press the croissant pieces down to ensure they absorb the egg liquid thoroughly.
- Refrigerate Overnight: Cover the dish tightly with plastic wrap and refrigerate for at least 8 hours or overnight to allow the flavors to meld and the croissants to soak up the custard.
- Preheat and Rest: Remove the dish from the fridge about 30 minutes before baking to take the chill off. Preheat the oven to 350°F.
- Bake: Remove the plastic wrap, sprinkle the remaining Gruyere cheese evenly over the top, and bake uncovered for 45 minutes until the top is golden brown and the egg custard is set.
- Finish and Serve: Before serving, top with extra Parmesan cheese and a sprinkle of fresh chopped parsley for color and flavor. Serve warm and enjoy your hearty breakfast bake!
Notes
- This dish is best prepared the night before and baked fresh the next morning, making it convenient for busy mornings or leisurely brunches.
- Baking the croissants before assembling ensures they stay crisp and soak up the egg mixture perfectly.
- Feel free to customize the herbs and vegetables based on your preference or seasonality.
- Gruyere cheese provides a nutty, creamy flavor, but you can substitute with Swiss or cheddar if needed.
- Covering and refrigerating allows the flavors to develop and the croissants to become custardy without getting soggy.
Nutrition
- Serving Size: 1 slice (of 8)
- Calories: 420
- Sugar: 4g
- Sodium: 370mg
- Fat: 28g
- Saturated Fat: 14g
- Unsaturated Fat: 12g
- Trans Fat: 0.5g
- Carbohydrates: 25g
- Fiber: 2g
- Protein: 15g
- Cholesterol: 260mg
