Cheese-filled omelette

This is one of my favourites for breakfast when I have enough time to cook something in the morning.

Ingredients:
3 eggs
Grated cheddar
A few slices of onion
Salt
Pepper
A little olive oil or butter

Cooking:
1) Beat the eggs and add a little salt and pepper
2) Chop the onion into small chunks.
3) Toss the onion into the frying pan with some olive oil or butter and leave for a few minutes until they've started cooking.
4) After the onions have started to go brown toss the eggs into the pan. Before this it's important that there is enough oil on the pan so it can turn without breaking up the omelette, and that the pan is hot enough so it can cook well in the middle after it's turned.
5) Sprinkle the grated cheddar all over the top while the bottom of the omelette is cooking for about 30 seconds.
6) Lifting it carefully so it doesn't break up, toss one half of the omelette over the other so it's in a semi-circle shape.
7) Turn off the heat on the pan so it doesn't overcook, and after another 30 seconds turn it to make sure it's fully cooked all through, which it should be by then. Take off the pan as soon as it's done and it's ready to eat.