Line baking trays with foil. Pipe the mixture, shaping into 25 small balls on the trays. Put the trays into the freezer for 1 hr or until you’re ready to serve them. Put the milk chocolate for coating into a heatproof bowl and heat in the microwave until melted, stirring after every 30-second blast. Alternatively set the bowl over a pan of simmering water to gently melt the chocolate. Drop a frozen truffle into the melted chocolate and turn it over with a spoon to coat it, then place back onto the foil-lined tray. Repeat with the rest of the truffles. The coating should set in about 5-10 mins.