Heat a non-stick frypan on medium heat. Use paper towel and wipe the pan with butter.
In a bowl gently whisk eggs and water with a fork. Pour mixture into pan, cook for 3-4 minutes or until the egg is no longer runny on top. Gently slide an egg flip around the edge of one side, slide it under the omelette to the middle of the pan and flip over to the other side.
Season to taste
Before flipping the omelette filling can be added. A small amount of filling makes it easier to flip and there's less chance of breaking the omelette. Be careful with fillings that have a high amount of water content such as tomato as this will make the omelette fall apart.
Cheese: cheddar, feta, parmesan