Melt the butter, mix in the flour and cook for 1-2 minutes.

Mix with the milk over the heat until it starts to boil.

Leave sauce to simmer. It should be very thick.

Season with salt, pepper and nutmeg and remove from the heat.

Add the egg whites, but don’t let them cook. Whip until they stand firm and mix in a bowl with the 100g gruyère.

Mix really well and pour into a buttered soufflé dish.

Sprinkle with cheese and cook for 20 minutes at a medium temperature.

Serve immediately on a bed of mixed salad.