Easy Mushroom Omelet

I'm not a morning person, I don't eat breakfast often and here I am ready to change my body clock! Easy Mushroom Omelet, my first recipe for my diet challenge, adapted from The South Beach Diet Recipes. The original recipe should be Easy Asparagus and Mushroom Omelet, but there's no asparagus available. Instead, I garnished it with freshly sliced tomatoes.

1 egg, beaten
2 tablespoon mushroom ( I used 2 white, chopped)
some mozzarella cheese
olive oil
salt to taste

In a pan, heat olive oil over medium-high heat. Pour in the egg mixture, it should set immediately. Fill one half of the omelet with mushrooms and cheese. Fold the omelet in half over the filling. Serve immediately.