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Egg Bake

Croissant Sausage and Mushroom Egg Bake

  • Author: Cosette's Kitchen
  • Prep Time: 25 minutes
  • Cook Time: 40 minutes
  • Total Time: 1 hour 5 minutes
  • Yield: 8-10 servings 1x
  • Category: Brunch
  • Method: Baking
  • Cuisine: American


A simple and delicious egg bake, perfect for weekend brunch.


  • 8 large croissants, sliced in half
  • 2 Tbsp of Olive Oil, divided
  • 1 large onion, thinly sliced
  • 2 tsp kosher salt, divided
  • ½ pound cremini mushrooms, sliced
  • ½ pound of ground/seasoned breakfast sausage*
  • 8 large eggs
  • 2 cups of whole milk
  • 1 ½ cups heavy cream
  • ½ tsp black pepper
  • 1 tsp garlic powder
  • 1 tsp Italian seasoning
  • 2 cups (8 oz) shredded or cubed cheese, I used sharp cheddar and gouda*
  • Chopped scallions
  • Everything but the bagel seasoning (optional)



  1. In a large skillet heat 1 Tbsp olive oil on medium-high heat.
  2. Add in your sliced onions and cook for 3-4 minutes until they become slightly translucent. Continue cooking and add your sliced mushrooms.
  3. Cook for another 3-4 minutes and add 1 teaspoon of your kosher salt.
  4. Next add your ground sausage and allow mixture to fully cook for another 4-5 minutes.
  5. Meanwhile, heat your oven to 500 degrees and prep your croissants to toast.
  6. Slice each croissant in half and place on a sheet pan (should have 16 pieces), drizzle lightly with the remaining olive oil, cut side up. (will probably need 2 sheet pans).
  7. Toast slightly in the hot oven for only 2-3 minutes until croissants begin to brown. Remove and set aside.
  8. In a large bowl, whisk your eggs, milk, heavy cream, black pepper, garlic powder, Italian seasoning and 1 teaspoon of your kosher salt. 
  9. Butter or spray a 9×13 baking dish and place one layer of croissant (cut side up) in your baking dish, it’s okay to layer them. Bottom layer should have about 6 halves.
  10. Drizzle some of your onion/mushroom/sausage mixture and half of your cheese.
  11. Layer another layer of croissant, again ok to layer and be sure to fill in the center, you can tear croissants if needed (it will get covered so doesn’t have to be pretty).
  12. Add the rest of your onion/mushroom/sausage mixture and cheese.
  13. Carefully pour your egg/milk mixture on top of the bake. Press croissants slightly into dish to coat.Cover with foil and allow to sit in fridge for at least 4 hours, great to make the night before.
  14. The next day, pop into a 350 degree oven covered with foil for 30 minutes. After 30 minutes, remove foil and bake for another 10 minutes.
  15. Remove from oven, top with scallions and a sprinkle of Everything but the Bagel spice (if you have).
  16. Enjoy warm or at room temperature.


  • You can choose any type of breakfast sausage you’d like, I like a mild variety but a spicy would be delicious as well.
  • You any combination of cheese you’d like, a sharp works very well in this dish.
  • This dish is best prepared the night before and baked in the morning, perfect for a holiday gathering.

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