Whip butter and sugar together in a bowl until super creamy.
Add whipping cream slowly until totally incorporated.
Cover a baking sheet with parchment paper.
Put mixture into piping bag and pipe small mounds spaced 1 inch apart on the parchment paper. You can also use a spoon and drop small mounds of mixture onto the baking sheet. Place a toothpick in each truffle.
Place the baking sheet in the fridge for an hour or put it in the freezer for approx. 15 minutes.
In the meantime melt the chocolate au-bain-marie or in the microwave.
Scoop a fair amount of cocoa powder in a dish.
Take a truffle by the toothpick and submerge it in the chocolate. Swivel it around to get rid of the excess chocolate.
Place the truffle in the cocoa powder and use a spoon to cover it with the cocoa powder. Allow the cocoa powder to stick to the chocolate and the chocolate to harden just a few minutes.
Place the truffles on a baking sheet and repeat process.