Start by finely chopping the dark chocolate with a serrated knife and place it into a heatproof bowl.
In a small saucepan, gently heat the cream over medium heat until it reaches a simmer—be cautious not to let it boil. The cream should be hot to the touch but not bubbling.
Immediately pour the warm cream over the chopped chocolate, covering the bowl. Let it sit undisturbed for 3-5 minutes, allowing the heat to soften the chocolate. Then, whisk the mixture until the chocolate and cream blend into a smooth, shiny ganache.
Transfer the ganache to a smaller bowl, cover it with plastic wrap, and refrigerate for at least two hours or until it becomes firm.
Once set, sift the cocoa powder into a separate bowl. Using a cookie scoop, measure out about one level tablespoon of ganache for each truffle. Roll each portion between your palms until smooth and round.
Toss the truffles in the cocoa powder, ensuring they are fully coated. Place each finished truffle on a plate. Repeat the process until all the ganache is used.
Store the truffles in the fridge for optimal freshness.