Mix together in a bowl two eggs, two table spoons of water and a dash of salt together with a whisk (or fork).
now grab a medium sized frying pan and melt butter in the pan or alternatively spray pan with oil.
once the pan is hot enough and the butter has completely melted pour in the mixture.
when the mixture looks partly cooked ( may still be a little watery on top, that is fine) add two slices of cheese the the middle of the omelette then flip one side up over the other side with a spatula so it is now in half and the cheese is in the middle.
let it cook for a little longer so the cheese melts ( being careful not to let it burn though)