Spray an 8-inch pan with olive oil and heat over medium heat. Add in the onions and bell peppers and any extra vegetables and meat if desired. Cook until bell peppers and onions are tender and then push vegetables to one side.
Turn heat to medium-low and then spray the other half with olive oil. Then slowly pour in the egg whites. Twirl the pan so the egg whites run all around the pan and under the vegetables. Add cheese on top of the vegetables and season with salt, pepper and garlic powder. Then cook until the egg whites have bubbled and cooked underneath.
Turn the heat off. Then carefully flip the egg over the vegetables with a spatula (or two).
Place omelette on plate and top with tomatoes and hot sauce if desired. Sprinkle on a little parmesan cheese if desired. Serve while hot.