Blender Soufflé Omelette

0 In a medium or large skillet, heat olive oil on medium-high heat. Begin to sauté the diced onions for 3 minutes, then add in the mushrooms and spinach. Season with salt and pepper.
1 Continue to sauté for 5 minutes or until most of the retained water has evaporated. Place the sautéed veggies in a strainer and set aside.
2 To a high-speed blender, add the 1 cup liquid egg whites, cream of tartar, and a pinch of salt. Blend on low for 3 whole minutes.
3 Clean the skillet you used, then place it back on the stove on medium-high heat. Spray the skillet with cooking oil spray or brush the skillet with olive oil.
4 Once the skillet has heated, pour in the half of the egg white mixture. Allow it to cook for about 2 minutes. At this point, you will notice the egg whites begin to solidify and get fluffy.  If you want it really thick then use the full cup of egg whites to make one omelette.
5 On one end of the round egg whites, add the sautéed veggies, top with shredded cheese, and cover to cook for another 2-3 minutes.
6 At this point, the cheese has melted and the egg whites have cooked. Using a spatula, fold one end of the round egg white over to cover the sautéed veggies and press.
7 Carefully slide it onto a serving dish and enjoy right away. Delicious with hot sauce.