Heat oven to 180C/fan 160C/gas 4. Put milk, onion, nutmeg and bay leaves into a pan. Bring to the boil, then set side to infuse for 30 mins. Butter 8 x 150ml ramekins.
Melt the butter in a second saucepan. Stir in the flour and cook gently for 1 min, stirring. Take off the heat and gradually whisk in the milk until smooth. Discard onion and bay leaf. Return to the hob and stir until the sauce boils and thickens.
Off the heat, stir in the mustard, egg yolks and three-quarters of the cheese, then season. Scrape mixture into a large mixing bowl. In another big bowl, whisk the egg whites until stiff. Boil a full kettle. Carefully fold the whites into the cheese mix and fill ramekins twothirds full. Transfer to a roasting tin, then pour the boiling water into the tin until it reaches halfway up the ramekins. Bake for 15-20 mins or until risen, just set and still a little wobbly. Take out of the tin and leave to cool.
To serve, heat oven to 220C/fan 200C/gas 7(or leave it at 190C/fan 170C/gas 5 if you are cooking the lamb). Loosen soufflés around the edges with a knife, then turn out, upside down, into a shallow ovenproof dish. Sprinkle
with rest of cheese, then spoon 1 tbsp cream over each soufflé. Bake for 10-12 mins till puffed and golden on the top (or 12-15 mins at the lower temperature). Serve at once with Crunchy celery & apple salad, below.