Description
A decadent and comforting Overnight Croissant Breakfast Bake featuring toasted buttery croissants, sautéed mushrooms and spinach, rich eggs with cream and milk, and melted Gruyere cheese. Prepared the night before and baked to golden perfection the next morning, this dish makes a perfect hearty breakfast or brunch.
Ingredients
Scale
Croissants
- 5 to 7 large croissants, sliced in half lengthwise
- 2 tablespoons unsalted butter, plus extra for brushing
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
Cheese
- 8 ounces Gruyere cheese, freshly grated
- Parmesan cheese, for topping
Instructions
- Toast the 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 toasted and slightly crispy. Remove from oven and let cool slightly, then chop or tear into pieces.
- Sauté Vegetables: In a large skillet, heat butter over medium-low heat. Add diced onions and minced garlic, cooking for 5 minutes until softened. Add chopped mushrooms and continue to cook for another 5 minutes until mushrooms are plump. Stir in fresh spinach and cook until wilted. Season generously with kosher salt and pepper, then stir to combine.
- Prepare Baking Dish: Brush a 9×13 inch baking dish with melted butter. Add the toasted croissant pieces to the dish and toss together with the sautéed vegetable mixture until combined.
- Mix Egg Custard: In a large bowl, whisk together eggs, milk, heavy cream, salt, and pepper until fully blended. Stir in 1 cup of the freshly grated Gruyere cheese and optional fresh chopped herbs like parsley and chives.
- Combine and Refrigerate: Pour the egg mixture over the croissant and vegetable mixture in the baking dish. Press croissant pieces down gently to ensure they absorb the liquid. Cover the dish with plastic wrap and refrigerate for at least 8 hours or overnight.
- Preheat for Baking: Remove the casserole from the fridge 30 minutes before baking to take the chill off. Preheat the oven to 350°F.
- Bake the Casserole: Remove the plastic wrap and sprinkle the remaining Gruyere cheese evenly over the top. Bake uncovered for 45 minutes until the custard is set, the top is golden, and the cheese is melted and bubbly.
- Finishing Touches and Serve: Once baked, top with extra Parmesan cheese and a sprinkle of fresh chopped parsley. Serve warm and enjoy this rich, flavorful breakfast bake.
Notes
- This dish is ideal for preparing the night before, making busy mornings easier and more delicious.
- To add extra flavor, fresh herbs like thyme or chives can be included in the egg mixture.
- If preferred, substitute Gruyere with Swiss or sharp white cheddar cheese.
- Make sure the croissants are properly toasted to avoid sogginess in the final bake.
- Leftovers keep well refrigerated for 2-3 days and can be reheated in the oven or microwave.
Nutrition
- Serving Size: 1 slice (approx. 1/8 of casserole)
- Calories: 410 kcal
- Sugar: 4 g
- Sodium: 350 mg
- Fat: 28 g
- Saturated Fat: 15 g
- Unsaturated Fat: 11 g
- Trans Fat: 0.5 g
- Carbohydrates: 25 g
- Fiber: 2 g
- Protein: 15 g
- Cholesterol: 220 mg
