Recipes provided by SweetRedPeppers.com.
1. Heat oven to 350 degrees. Brown the sausage in a hot skillet over medium flame, breaking up the meat as it cooks. Add the onions about half-way through the browning time, and let them cook with the sausage. Lightly grease a 9-by-13-inch baking dish. Spread sausage and onion mixture in dish.
2. Mix eggs, potatoes, cheeses and mustard. Spread over sausage mixture. Bake until set, about 40 minutes. Let stand 5 minutes before cutting into squares or rectangles for serving.