From The Blue Apron, via The Art of Manliness blog.
This isn't how I do my omelets. I prep the mushrooms and asparagus, for example, before I fix the omelet. But I dump it, along with some peppers, spinach, and tomatoes in after I pour the egg whites in. (I use egg whites only because of my heart situation.) I may have to try this technique...sans flipping it with the pan because I am not a seasoned chef.