Description
This Overnight Croissant Breakfast Casserole is a savory, comforting dish perfect for feeding a crowd or enjoying leisurely mornings. It features tender croissant pieces baked with savory breakfast sausage, sautéed onions, and sharp cheddar cheese soaked in a flavorful custard made with eggs, cream, and milk. The casserole is baked until golden and served with a rich, creamy sausage gravy made from the reserved sausage fat, butter, flour, and milk. Prep it the night before for an easy, impressive breakfast.
Ingredients
Scale
For the Casserole
- 1 tablespoon olive oil
- 1 small onion, peeled and diced
- 1 pound breakfast sausage (mild flavor)
- 4 large croissants (or 8 small croissants), torn into large bite-size pieces
- 1 cup shredded cheddar cheese
- 6 large eggs
- ½ cup heavy whipping cream
- 3 cups milk (whole milk recommended, divided)
- ½ teaspoon dry mustard powder
- ½ teaspoon salt, plus additional to taste for the gravy
- ½ teaspoon black pepper, plus additional to taste for the gravy
- ¼ teaspoon paprika
- ¼ teaspoon garlic powder
For the Gravy
- 2 tablespoons butter
- 3 tablespoons all-purpose flour
- 1 tablespoon reserved sausage fat (from cooked sausage)
Instructions
- Sauté onions and cook sausage: Heat olive oil in a large skillet over medium heat. Add diced onions and sauté until soft and translucent. Crumble in the breakfast sausage and cook until fully browned. Drain excess fat, reserving about 1 tablespoon for the gravy, and store it refrigerated overnight.
- Assemble casserole base: In a large bowl, combine the cooked sausage and onions with torn croissant pieces and shredded cheddar cheese. Transfer the mixture into a greased 9×13-inch glass baking dish.
- Prepare custard mixture: In a medium bowl, whisk together eggs, heavy whipping cream, ½ cup milk, dry mustard powder, salt, black pepper, paprika, and garlic powder until smooth. Pour evenly over the croissant and sausage mixture in the baking dish.
- Refrigerate overnight: Cover the dish tightly with plastic wrap and refrigerate for at least 8 hours or overnight to allow the custard to soak into the croissants.
- Preheat oven: Remove the casserole from the fridge and preheat the oven to 350°F (175°C).
- Bake the casserole: Bake uncovered for 35-45 minutes until the top is golden brown and the custard is set.
- Make sausage gravy: While casserole bakes, melt butter with 1 tablespoon reserved sausage fat in a medium saucepan over medium heat. Whisk in the flour to create a roux and cook for 1 minute, stirring constantly.
- Add milk and thicken gravy: Gradually whisk in the remaining 2½ cups milk, stirring continuously to avoid lumps. Simmer on low heat for 2-3 minutes until the gravy thickens. Season with salt and pepper to taste.
- Serve: Cut the casserole into portions and serve warm, topped or sided with the sausage gravy.
Notes
- For best texture, use day-old croissants or slightly stale for better custard absorption.
- Store leftover casserole covered in the refrigerator for up to 3 days.
- The reserved sausage fat is key for flavorful gravy; do not discard it.
- Use whole milk for a richer casserole and gravy, but you can substitute 2% milk if preferred.
- This recipe can be prepared the night before to save morning time.
- Adjust the seasoning of the gravy according to your taste.
