01 - Place the finely chopped dark chocolate in a heatproof bowl.
02 - In a small saucepan, heat the heavy cream over medium heat until it just begins to simmer; do not boil.
03 - Pour the hot cream over the chopped chocolate. Allow it to stand for 2 minutes, then gently stir until the chocolate is smooth and fully melted.
04 - Add the unsalted butter and stir until fully incorporated and glossy. If using, stir in the vanilla extract and liqueur.
05 - Cover the bowl with plastic wrap and refrigerate for at least 2 hours, or until the ganache is firm enough to handle.
06 - Line a baking sheet with parchment paper to prepare for coating.
07 - Using a small spoon or melon baller, scoop out uniform portions of the chilled ganache and roll them into balls between your palms (wearing food-safe gloves is recommended if desired).
08 - Roll each truffle in your chosen coating, such as cocoa powder, chopped nuts, or grated coconut, to fully coat its surface. Place the coated truffles on the prepared baking sheet.
09 - Refrigerate the finished truffles for 30 minutes before serving. Store truffles in an airtight container in the refrigerator for up to 1 week.