Thinly slice the celery.

Melt the butter in a saucepan and quickly fry the celery, sprinkle with the flour and cook for a few minutes. Stir in the milk and simmer until thick, stirring continuously. Season with salt, pepper and nutmeg. Allow the sauce to cool.

Grease four 8 cm (3 in) deep individual souffle dishes.

Whisk the egg whites until stiff. Gradually beat the egg yolks and cheese into the cooled sauce. Stir in a little of the egg white, then carefully fold in the remainder, using a metal spoon. Divide the mixture between the prepared souffle dishes.

Bake the cheese souffles in a moderate oven (180°c, 350°f, gas 4) for 30 minutes, until golden brown. On no account should the oven door be opened during the first 15 minutes. Serve hot.