Heat oven to 350°F. In 13x9-inch (3-quart) glass baking dish, melt butter in oven; tilt dish to coat bottom.
In large bowl, beat eggs and cooking sauce with fork or whisk until blended. Stir in cheese and ham. Pour into baking dish.
Bake uncovered about 30 minutes or until eggs are set but still moist. Sprinkle with onions, mushrooms and tomato.