Preheat oven to 350º.Cook sausage in a skillet.Spray medium (9 x 13) casserole dish with non-stick spray.In casserole dish, scatter diced hash browns, top with ½ cheese followed by crumbled cooked sausage. Add veggies.In a medium bowl, beat eggs and milk. Add salt and pepper, to taste.Pour eggs over casserole. Top with cheese.Cover and store in refrigerator overnight or bake immediately.Bake covered (with lid or aluminum foil) for 50 minutes. Uncover and return to oven, cook uncovered for an additional 10 minutes.Allow casserole to rest for 15-20 minutes.