In a small pan warm the milk over a very low heat with 2 sprigs of thyme. Do this while preparing the rest of the dish, but do not allow the milk to boil. Peel and very thinly slice the potatoes then swirl around under running water in a colander to wash away some of the starch. Trim and wash leeks and also slice thinly. Crush the garlic clove and grate the cheese. Grease a shallow gratin dish with the butter and then arrange layers of potato and leek with a little of the garlic, nutmeg and seasoning. Remove the thyme from the milk and lay over the vegetables, then sprinkle with grated cheese. Bake in a moderate oven until golden brown. DISCLAIMER? Copyright 1996 - SelecTV Cable Limited. All rights reserved. Carlton Food Network http://www.cfn.co.uk/