The main difference between the two is the set of ingredients mixed in the eggs. While Omelette generally uses only onion, tomato, green chilies, and basic spice powders, Egg Fooyung uses garlic, various veggies, meat, five-spice powder, and red chili flakes. Omelette is cooked in less oil while Egg Foo Yung is fried in oil. Also, Omelette is just cooked and served as it is or with Toast, but Egg Foo Young is served with a delicious sauce.