Fried cubed green bell and mushroom for about 3 mins ( you can add pinch of salt and pepper ).
Then, add sausage crumbles and fried it for about 5 mins. Remove them from pan and set aside on a plate.
Stir the eggs and egg whites lightly. Then, cook them in skillet until set (medium heat).
Add the crumbles, bell pepper, mushroom and mozzarella cheese on top.
Fold omelet over and heat until cheese is melted.