Halve an onion and stud each half with 4 cloves. Put into a pan with 600ml full-fat milk, 2 fresh bay leaves and 8 black peppercorns. Slowly bring to simmering point, remove from the heat and set aside for 1 hour to infuse. Strain the milk into a clean pan, discarding the solids. Add 115g fresh white breadcrumbs and 25g butter to the pan, bring back to simmering point, stirring, then set aside for 15 minutes to thicken. Reheat just before serving, then stir in 4 tablespoons crème fraîche and season. Serve hot with a little grated nutmeg on top. This will keep, covered, in the fridge for up to 24 hours.