01 - 
                Gather all ingredients. If using whole eggs, crack them into a bowl. Grate the cheese and chop the green onions if using.
              
              
              
                02 - 
                Whisk the eggs or egg whites vigorously until they become frothy. Add a pinch of salt while beating.
              
              
              
                03 - 
                Heat a non-stick skillet over medium heat. Add the cooking oil and ensure it coats the entire surface of the pan.
              
              
              
                04 - 
                Pour the beaten eggs into the hot pan. As the edges start to set, use a spatula to gently pull the cooked edges toward the center, allowing uncooked egg to flow to the edges.
              
              
              
                05 - 
                When the omelet is mostly set but still slightly wet on top, add the grated cheese and chopped green onions (if using) to one half of the omelet.
              
              
              
                06 - 
                Add the butter in small pieces around the edges of the pan. This will melt and help create a golden exterior. Fold the omelet in half over the fillings and cook for another minute.
              
              
              
                07 - 
                Slide the omelet onto a plate and serve immediately while it's still hot and fluffy.