Cook bacon in a medium skillet until crisp; remove bacon, and drain on paper towels, reserving 1 teaspoon drippings in skillet. Crumble bacon, and set aside.
Add 1/2 cup chopped onion to hot drippings in skillet, and sauté over medium heat 3 to 4 minutes or until tender.
Stir together crumbled bacon, onion, egg substitute, and next 5 ingredients in a large bowl. Pour egg mixture into a 13- x 9-inch baking dish coated with cooking spray.
Bake at 325° for 45 minutes or until set. Let stand 5 minutes before serving. Garnish, if desired.