Preheat oven to 200°C (180°C fan) and butter 8x8cm (150-200ml capacity), or 4x10cm (300ml capacity) soufflé dishes or ramekins with 50g softened butter and coat with 50g grated cheese. Line a baking dish with folded teatowel; arrange soufflé dishes in baking dish.

Melt 20g butter in a pan, add flour and stir constantly over moderate heat for 2 minutes. Remove from heat and stir in the milk all at once. Return to heat and bring to a boil over moderate heat. Cook 2 minutes, then pour into bowl. Season with salt, pepper and cayenne. Stir in egg yolks. Cool slightly.

Beat egg whites with a pinch of salt until soft peaks form, then stir one third of the whites into the sauce until incorporated. Add the remaining whites and fold in gently while adding grated cheese (don't over-mix). Spoon into dishes and level the top with a spatula. Run your thumb around the inside top of the dishes.

Pour enough hot water into the baking dish to come halfway up the sides of the dishes. Bake for about 18-25 minutes, until soufflés are well-risen and firm. Serve immediately.