1. Place sausage on a 15-inch x 10-inch x 1-inch baking pan.
2. Bake at 375˚F for 15 to 20 minutes or until sausage is no longer pink and an internal temperature of 165˚F is reached, turning once; drain and slice into 1/4-inch coins.
3. In a large bowl, combine the eggs, milk, mustard, salt and pepper.
4. Add the hash browns, sausage, cheese, sweet red pepper and green onions; mix well.
5. Pour into a greased 13-inch x 9-inch x 2-inch baking dish.
6. Cover and refrigerate overnight.
7. Remove from the refrigerator 30 minutes before baking.
8. Bake, uncovered, at 350˚F for 65 to 70 minutes or until set and golden brown and an internal temperature of 165˚F is reached.
9. Let stand 10 minutes before serving.
10. Serve with salsa or picante sauce if desired.