In a large skillet heat ½ teaspoon of olive oil on medium, add in the bell pepper, mushrooms and tomatoes.
Cook for 10 minutes until the bell peppers are soft, while they cook prep the eggs and shred the cheese.
Once the veggies are done cooking add in the green onion, turn off the heat and cover.
In a small skillet heat the remaining ½ teaspoon olive oil on medium low. Whisk the egg whites and eggs together with a tablespoon of water until light and airy and add to the small skillet.
Let the eggs cook slowly undisturbed until ½ of the eggs have set.
Use a spatula to gently lift one side of the omelet so that the runny eggs can pool below, then lay back down the cooked eggs and top the entire top of the omelet with cheese and cooked veggies.