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Croissant Breakfast Casserole Recipe

This Croissant Breakfast Casserole Recipe combines buttery croissants, savory eggs, creamy cheese, and your favorite fillings into a decadent, make-ahead brunch dish that’s perfect for holidays, gatherings, or lazy weekend mornings.
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Prep Time 20 minutes
Cook Time 45 minutes
Course Breakfast
Cuisine American
Servings 8
Calories 480 kcal

Ingredients
  

Base Ingredients:

  • 6 large croissants preferably day-old, torn into 2-inch pieces
  • 8 large eggs
  • 2 cups whole milk or use half-and-half for a richer texture
  • 1 cup heavy cream
  • 1 ½ cups shredded cheese cheddar, Gruyère, or Swiss
  • 1 tsp Dijon mustard
  • ½ tsp garlic powder
  • ½ tsp onion powder
  • Salt and black pepper to taste

Optional Add-Ins (choose your favorites):

  • 1 cup cooked bacon crumbled
  • 1 cup breakfast sausage cooked and crumbled
  • 1 cup sautéed spinach or kale
  • ½ cup caramelized onions
  • 1 cup cherry tomatoes halved
  • ½ cup diced bell peppers
  • ½ cup chopped scallions

Instructions
 

Step 1: Prepare Croissants

  • Tear croissants into 2-inch pieces. If fresh, dry them in a 300°F oven for 10 minutes to remove excess moisture.

Step 2: Grease the Baking Dish

  • Lightly butter or spray a 9x13-inch baking dish. Spread half of the croissant pieces in the dish.

Step 3: Layer the Fillings

  • Add your chosen meats or vegetables and sprinkle with half the cheese. Repeat with remaining croissants, fillings, and cheese.

Step 4: Make the Egg Mixture

  • In a large bowl, whisk together eggs, milk, cream, Dijon mustard, garlic powder, onion powder, salt, and pepper until smooth.

Step 5: Assemble and Soak

  • Pour the custard evenly over the croissants. Gently press down to help absorption. Let sit for 30 minutes, or refrigerate overnight.

Step 6: Bake

  • Preheat oven to 350°F (175°C). Cover casserole loosely with foil and bake for 30 minutes. Remove foil and bake an additional 15–20 minutes until golden and set in the center.

Step 7: Rest and Serve

  • Allow to rest for 10–15 minutes before slicing and serving.

Notes

  • Make-Ahead Tip: Assemble the night before and refrigerate—just bake in the morning!
  • Cheese Combos: Try mixing cheddar with Gruyère or Swiss for added depth.
  • Storage: Refrigerate leftovers in an airtight container for up to 4 days. Freeze slices for up to 2 months.
  • Reheating: Warm in the microwave or oven at 300°F until heated through.
  • Vegetarian Option: Skip the meat and load up on vegetables like spinach, mushrooms, and tomatoes.
  • Flavor Boost: Add fresh herbs like thyme or chives before baking.