I’m going to show you how to make the perfect cheese omelette because it's my favourite, but if you’re going to use something like mushrooms, onions, peppers or anything like that saute them in a pan for a few minutes first just to bring out the flavour.
For a medium size pan break 3 eggs into a bowl, season with salt and pepper
(as in scrambled I use ground white pepper because I just don’t like the look of black bits in the finished dish) and whisk a little more than you would for scrambled but don’t go mad and certainly don’t use an electric whisk.
Put the pan on a medium heat with a couple of knobs of butter and then pour in the egg mixture, for the first half a minute give the pan a shake and give the mixture a stir and then let it settle.
When the underside has started to cook dump a good handful of grated cheddar into the uncooked top layer of egg and leave to cook for a minute.
When the time comes that you would normally want to flip it over to cook the other side, don’t!! Sprinkle some more grated cheese over the top and put it under the grill.
Keep an eye on it, don’t leave it there for too long, just until the egg fluffs up and the layer of cheese melts.
Slide it on a plate and fold it in half.