Place all the ingredients in a large heatproof bowl and place over a pan of simmering water. Stir constantly until all has melted and combined into gooey, chocolatey awesomeness.
Place in the refrigerator and allow to cool completely (3 to 4 hours but up to 6 is preferred)
Remove from the refrigerator. With a teaspoon/ melon baller/ cookie dough scoop or similar, scoop out the desired amount of truffle and roll between your hands to form a ball. Roll in the cacao powder and place on a plate or container.
Can be enjoyed immediately (it is best to serve them whilst chilled otherwise they melt and become gooey and sticky - not a completely terrible situation but not quite the desired effect) or stored in the refrigerator for up to a week.