Preheat oven to 350 degrees and prepare a 9x13 baking dish with cooking spray.
Chop sausage, onion, peppers and mushrooms.
In a separate bowl mix eggs, sour cream and cheese.
Once egg mixture is thoroughly mixed, add sausage and veggies. Pour into your prepared dish.
Bake for 45 minutes or until cooked through.
Video
Notes
Make ahead: Assemble the casserole the night before but don't bake it. Cover with plastic wrap, refrigerate, and pop it into the oven the next morning. Since there are so many veggies, we like to use afood processor to chop everything!