1) Preheat oven to 325
2) Lightly coat a 9 x 13 baking dish with cooking spray.
3) Layer potatoes evenly on the bottom of the dish; top with ham, mushrooms and onions.
4) In a small mixing bowl, beat egg substitute and skim milk with a fork or whisk until well blended.
5) Pour egg mixture over ham and vegetables in baking dish and top with cheese.
6) Bake until eggs are firm and top is lightly browned, approximately 40 minutes.
7) Cut into 4 portions. Serve and enjoy!