Chop the onion, green chilli and coriander quite finely and beat the eggs and milk together with salt and pepper.
Heat the oil in a small frying pan and pour in the eggs and keep them moving until two thirds have scrambled. 3) Settle the eggs back down on the base of the pan, scatter over the cheese and cook for about a minute until the omelet is just set and the cheese has melted.
Carefully fold the omelet using a spatula and slide from the pan to a serving plate.
Eat while the omelet is hot and the cheese still melted.