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Overnight Sausage Croissant Breakfast Casserole with Leeks

Prep Time10 mins
Cook Time1 hr 13 mins
Total Time1 hr 23 mins
Course: Breakfast, Brunch
Keyword: breakfast, casserole, sausage
Servings: 8


  • 1 tbsp butter
  • 12 oz breakfast sausage (removed from casing, or ground)
  • 1 leek- tough ends removed, cleaned halved lengthwise and sliced thinly  
  • 10 large eggs
  • 1 1/4 cups heavy cream 
  • salt and fresh ground black pepper, to taste
  • 1 tsp garlic powder 
  • 6 medium-large Croissants, torn into small pieces 
  • 6 oz gruyere cheese, shredded 


  • Prepping the casserole
    1. In a large non-stick skillet, melt butter over medium heat.
    2. Add the sausage to the pan and cook, breaking up as you go, until brown, 5-6 minutes.
    3. Add the leeks to the pan with the sausage, season with salt and pepper, and cook, stirring occasionally, for 5-7 minutes- until leeks are softened.
    4. While sausage and leeks cook, tear up the croissants into small pieces, and layer in the bottom of greased 9”x13” glass or ceramic baking dish.
    5. Once sausage and leeks are ready, layer evenly over croissant pieces.
    6. In a large mixing bowl, whisk eggs and cream together, and season with salt, pepper and garlic powder.
    7. Pour egg mixture evenly over croissants, sausage and leeks.
    8. Top casserole with grated gruyere cheese, and cover the dish with foil.
    9. Refrigerate overnight. Can be made up to a day in advance.
    Bake the casserole
    1. Preheat the oven to 375 degrees.
    2. Bake the casserole covered for 30 minutes. After 30 minutes, uncover the dish and bake for an additional 25-30 minutes, until casserole is set, and top is brown and crispy. Allow to cool about 20 minutes before serving.