In a large skillet cook sausage until brown. Drain off fat.
Arrange 3 of the waffles in a 2-quart rectangular baking dish. Top with half of the sausage and about 1/3 cup of the cheese. Repeat layers.
In a large bowl beat eggs with a fork; stir in milk, mustard, and pepper. Pour over layers in dish. Cover and chill for at least 4 hours or up to 24 hours.
Preheat oven to 350 degree F. Uncover and bake in preheated oven for 50 to 60 minutes or until a knife inserted near center comes out clean. Sprinkle with the remaining 1/3 cup cheese. Let stand for 10 minutes before serving. If desired, serve on toasted waffles and drizzle with maple syrup. Makes 8 servings.