Break up the chocolate and add it to a heatproof bowl with the cream.
With adult supervision, gently melt both together over a pan of simmering water. Make sure the bowl doesn’t touch the water.
Stir until smooth, then take off the heat.
Pour the chocolate and cream mixture into a lined 2lb loaf tin. Place in the fridge overnight to set.
Once set, scoop out a teaspoonful of the mixture at a time.
Poke a “trick” (pickled onion or gherkin piece) or a “treat” (Smartie or Jelly Tot) into the centre of each portion.
Roll each portion into a ball the size of a chestnut.
Finish by rolling the truffle in cocoa powder.
Repeat with the remaining fillings.
Chill until ready to serve. Then let the games begin!