Using an 8-inch non-stick skillet, coat heavily with non-stick spray and add onions, and mushrooms. Season with salt and pepper. Cook onions and mushrooms over a low heat until the onions are transparent.
Pour Egg Beaters overcooked onions and mushrooms, and then sprinkle with spinach and allow the eggs to cook fully. When the eggs are done turn omelet over onto itself and allow the spinach to steam for a moment or two before serving. Service with fresh tomato slices, and serve with a 2 ounce serving of french baguette bread.
Of course, you could use other vegetables, and it would still be a healthy choice for breakfast. If you add things like cheese and meat, the calories would increase.