Put the pan on the fire.
Drop in the oil.
Let the pan sit on gentle heat to allow the oil to spread all over the bottom.
While the pan is heating up, break the egg into the bowl and beat with the wire whisk. (About 30-40 energetic strokes should be enough to blend the white and yolk well and make the mixture fluffy.)
Mix in the salt and pepper and immediately pour the mixture into the heated pan.
Turn the heat up to medium and let the egg cook on the underside.
After about a minute you can lift up an edge with the spatula and peek underneath.
If it has become a golden brown, tilt the pan and let some of the uncooked egg on top slide to the bottom.
Cover with the lid and cook another 30 seconds to 1 minute.
By this time, the egg should be done.
Fold the omelette in half with a spatula and gently slide onto a plate.