Ladies, this recipe was taken from here 'Magic of taste: Truffles with a note of citrous.'
Put into heavy pan a cream and bring to boil (don?t boil), take away from fire. Add pieces of chocolate, butter, espresso powder, orange zest and liqueur. Blend all with woody tablespoon until total dissolution of chocolate and butter. Refrigerate for 20 min in metallic cup. Remove from fridge and roll into cacao powder, finished balls bake into the fridge until to serve. Yummy! That tastes out of this world!
By the way, you can experiment with different additions, like a vanilla, lemon zest, nuts, even chilli etc.