Cut the onion in half and stick the cloves in it – how many you use is a personal matter; I happen to like a pronounced flavour of clove.If you don't like them at all, you can use some freshly grated nutmeg instead. Place the onion – studded with cloves – plus the bay leaf and the peppercorns, in a saucepan together with the milk. Add some salt then bring everything up to boiling point. Take off the heat, cover the pan and leave in a warm place for the milk to infuse for two hours or more.When you're ready to make the sauce, remove the onion, bay leaf and peppercorns and keep them on one side.Stir the breadcrumbs into the milk and add 1 oz (25 g) of the butter. Leave the saucepan on a very low heat, stirring now and then, until the crumbs have swollen and thickened the sauce – about 15 minutes. Now replace the clove-studded onion, the bay leaf and the peppercorns and again leave the pan in a warm place until the sauce is needed.Just before serving, remove the onion and spices. Reheat gently then beat in the remaining butter and the cream and taste to check the seasoning.Pour into a warm serving jug.