Warm a 20cm (measured across the top) non-stick frying pan on a medium heat
Crack the eggs into a bowl and beat them with a fork so they break up and mix, but not as completely as you would for scrambled egg
With the heat on medium-hot, drop one knob of butter into the pan
It should bubble and sizzle, but not brown
Season the eggs with the Parmesan and a little salt and pepper, and pour into the pan
Let the eggs bubble slightly for a couple of seconds, then take a wooden fork or spatula and gently draw the mixture in from the sides of the pan a few times, so it gathers in folds in the centre
Leave for a few seconds, then stir again to lightly combine uncooked egg with cooked
Leave briefly again, and when partly cooked, stir a bit faster, stopping while there’s some barely cooked egg left
With the pan flat on the heat, shake it back and forth a few times to settle the mixture
It should slide easily in the pan and look soft and moist on top
A quick burst of heat will brown the underside
Grip the handle underneath
Tilt the pan down away from you and let the omelette fall to the edge
Fold the side nearest to you over by a third with your fork, and keep it rolling over, so the omelette tips onto a plate – or fold it in half, if that’s easier
For a neat finish, cover the omelette with a piece of kitchen paper and plump it up a bit with your fingers