Sausage and Mushroom Breakfast Bake

In a large skillet, cook sausage and mushrooms over medium heat until meat is no longer pink; drain. Place half of the bread cubes in a greased 13-in. x 9-in. baking dish; top with 2 cups sausage mixture and half of the cheese and tomatoes. Repeat layers. In a large bowl, combine the eggs, milk, mustard, salt and pepper; pour over bread mixture. Let stand in refrigerator overnight. Let stand out of the refrigerator for 30 minutes then bake, uncovered, at 350° for 50-55 minutes or until a knife inserted near the center comes out clean. Let stand for 10 minutes before serving.