Prepare the Ingredients: Start by greasing a 9×13-inch baking dish. Tear the 6 large croissants into pieces and spread them evenly across the bottom of the dish.
Add the Sausage: Crumble the cooked turkey sausage and sprinkle it over the torn croissants. You can also use cooked turkey bacon for a different flavor.
Incorporate Vegetables: If you choose to include them, sprinkle the 1/2 cup diced bell peppers and 1/2 cup diced onions evenly over the sausage mixture.
Make the Egg Mixture: In a large bowl, whisk together the 8 large eggs, 2 cups of whole milk, and 1 cup of heavy cream. Add in 1/2 tsp garlic powder, 1/2 tsp smoked paprika, 1 tsp salt, and 1/2 tsp black pepper, mixing until fully combined.
Add Cheese: Fold in 2 cups of shredded cheddar cheese and 1/2 cup grated Parmesan cheese into the egg mixture, ensuring that the cheese evenly distributes.
Combine Mixtures: Pour the egg and cheese mixture over the croissant and sausage layers, making sure to soak all the bread pieces.
Chill Overnight: Cover the dish with plastic wrap and refrigerate overnight. This allows the croissants to soak up the egg mixture.
Bake the Casserole: The next morning, preheat your oven to 350°F (175°C). Remove the plastic wrap and bake the casserole for 45-55 minutes, or until the top is golden brown and a knife inserted in the center comes out clean.
Garnish and Serve: Remove from the oven and let it cool for a few minutes. Garnish with fresh parsley or chives before serving. Enjoy warm!