Creating the perfect Croissant Breakfast Casserole is easy when you follow these steps:

1. Preheat Oven: Set your oven to 350°F (175°C) so it’s ready for baking.
2. Prepare Croissants: Cut the croissants into bite-sized pieces and place them in a greased casserole dish.
3. Whisk Eggs: In a large bowl, whisk together the eggs, milk, salt, pepper, and Dijon mustard until combined.
4. Add Meat and Veggies: Fold in the cooked sausage or bacon, along with bell peppers and onions if using.
5. Combine with Croissants: Pour the egg mixture evenly over the croissant pieces in the casserole dish.
6. Add Cheese: Sprinkle the shredded cheese on top of the egg mixture.
7. Let it Soak: Allow the casserole to sit for about 10-15 minutes to let the croissants absorb the egg mixture.
8. Bake: Place the casserole in the preheated oven and bake for 35-40 minutes, or until the eggs are set, and the top is golden.
9. Cool Slightly: Once baking is complete, allow the casserole to cool for about 5-10 minutes before serving.
10. Garnish and Serve: Sprinkle with fresh herbs if desired and serve warm.

By following these steps, you’ll create an amazing Croissant Breakfast Casserole that everyone will love!