Combine egg whites, eggs, and pepper (if desired) in a small bowl; whisk to blend. Set aside.
Heat small nonstick skillet, lightly coated with spray, over medium heat.
Add mushrooms; cook, stirring frequently, for 4 to 5 minutes, or until mushrooms release their liquid.
Add tomato; cook, stirring frequently, for 2 to 3 minutes, or until tender. Remove from skillet. Lightly coat skillet with spray.
Place egg mixture in same skillet; cook, over medium-low heat. Do not stir. As eggs set, lift edges, letting uncooked portion flow underneath.
When eggs are almost set, add mushroom mixture, cheese, and bacon; cook for 1 to 2 minutes, or until cheese starts to melt. Gently fold in half.
Garnish with green onion and tomato (if desired).
The Nutrition Facts box below provides estimated nutritional information for this recipe.