Break up the chocolate into small pieces and place into a large bowl and set aside.
Add the double cream and butter to a saucepan, place over a low heat stirring gently until the butter has completely melted.
Pour the cream and butter mixture over the chocolate and stir until the chocolate has melted. The mixture will come together into a thick paste.
Leave aside to cool, cover and refrigerate for a minimum of two hours or overnight. [At this stage you can freeze this mixture. Simply defrost in the fridge when you are ready to finish.]
When ready to serve, remove from the fridge and leave to sit for half an hour. Use a teaspoon and roll the mixture into small balls in the palm of your hand. Roll the truffles in cocoa powder and serve.
Keep any leftovers in a sealed container in the fridge.
These have been dusted in cocoa powder, you could also use desiccated coconut or chopped nuts.