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two slices of egg casserole on a white plate
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Breakfast Sausage Casserole

This crowd pleasing Breakfast Sausage Casserole is made with the perfect combination of croissants, a creamy egg custard, cheese and pork sausage. It doubles as a great make-ahead week-day or weekend breakfast and always goes over well for holiday breakfast and brunch!
Course Breakfast
Cuisine American
Prep Time 20 minutes
Cook Time 35 minutes
Total Time 55 minutes
Servings 8 large slices
Calories 564kcal

Ingredients

  • 2 packages mini croissants* (14 oz.)
  • 1 lb. ground pork sausage
  • 1 Tbsp. unsalted butter
  • 1/2 white onion, diced small
  • 3 cloves garlic, minced
  • 1 cup Gruyere cheese, shredded
  • 8 large eggs
  • 1 1/2 cups whole milk
  • 1 cup heavy cream
  • 1 Tbsp. Dijon
  • salt and pepper
  • 1 cup mozzarella cheese, shredded

Instructions

  • Preheat the oven to 375°F. Cut the croissants into 1-inch cubes, or just tear apart with your hands. Spread on a sheet pan lined with parchment paper and toast for about 8-10 minutes. Remove from the oven and cool; turn off the oven.
    2 packages mini croissants* (14 oz.)
  • Meanwhile, cook the sausage in a saute pan over medium-high heat breaking it up with a wooden spoon until fully cooked. Drain the sausage in a colander and discard the grease. Pour the cooked sausage into a large mixing bowl.
    1 lb. ground pork sausage
  • To the same saute pan, melt the butter. Add the onions and cook, stirring occasionally, until fragrant, about 5 minutes. Add the garlic, stir for another 30 seconds or so. Transfer to the bowl with the sausage. Add the toasted croissants to the bowl, along with the Gruyere cheese. Stir until combined.
    1 Tbsp. unsalted butter, 1/2 white onion, diced small, 3 cloves garlic, minced, 1 cup Gruyere cheese, shredded
  • Grease a 9x13 inch casserole dish with baking spray and pour the sausage croissant mixture into the dish in an even layer.
  • In another mixing bowl whisk together the eggs, whole milk, heavy cream, Dijon mustard and heavy pinch of salt and pepper. Whisk until combined.
    8 large eggs, 1 1/2 cups whole milk, 1 cup heavy cream, 1 Tbsp. Dijon, salt and pepper
  • Pour the egg custard mixture over the croissants. Cover with plastic wrap and refrigerate for at least 1-2 hours, or up to 8 hours/overnight*
  • When ready to bake, preheat the oven to 375°F.
  • Sprinkle the mozzarella cheese on top. Bake uncovered for 35-40 minutes or until the tops are golden brown and the casserole is set. (Check around 30 minutes to make sure the tops aren't too browned, if they are cover with foil for the last few minutes).
    1 cup mozzarella cheese, shredded
  • Let the casserole rest for about 10 minutes before slicing. Garnish with chives, parsley, your favorite hot sauce or black pepper. Enjoy!

Video

Notes

    • *Croissants: Use a different bread if you aren't feeling like croissants some other great options are sourdough, ciabatta bread, Hawaiian sweet dinner rolls, a hearty white sandwich bread, baguette bread, etc. Really any bread will work well. 
    • Let it rest: all egg casseroles you'll come across are bound together with an egg custard and it's important to allow that custard to soak into the bread so everything can be distributed into the casserole to create a delicious breakfast. Soaking = cohesive casserole. Anywhere from 1-4 hours is plenty when using toasted croissants.
    • With that said...Don't soak the croissants for too long. Since croissants are really buttery and soft, if you let the casserole soak for any longer than 12 hours in the egg custard, the casserole has a tendency to get mushy. Be sure to toast the croissant pieces, and don't let it soak for too too long. If using another sturdy bread, you won't run into this issue as much but I typically only soak for 8ish hours.
    • Storage: Once the casserole is at room temperature, wrap the casserole, or individual servings in an air tight container and store in the refrigerator for up to 5 day. OR in the freezer for up to 2 months. Once ready to serve your pre-baked casserole, I always like to thaw it out in the refrigerator overnight. This way, when you pop it in the oven at 357°, it will reheat evenly.

Nutrition

Serving: 1slice | Calories: 564kcal | Carbohydrates: 42g | Protein: 27g | Fat: 42g | Saturated Fat: 20g | Polyunsaturated Fat: 4g | Monounsaturated Fat: 15g | Trans Fat: 0.2g | Cholesterol: 299mg | Sodium: 685mg | Potassium: 349mg | Fiber: 0.2g | Sugar: 4g | Vitamin A: 1125IU | Vitamin C: 1mg | Calcium: 352mg | Iron: 2mg