Place your chopped dark chocolate into a heatproof bowl, ready for the ganache base.

In a small saucepan, combine heavy cream, butter, and raspberry preserves; heat over medium-low heat until butter melts and the mixture just simmers, avoiding a boil.

Pour the hot cream mixture over the chopped chocolate and let it sit undisturbed for 5 minutes to allow the chocolate to melt thoroughly.

Whisk the chocolate mixture gently from the center outwards until it is completely smooth and glossy, then stir in the vanilla extract.

Cover the bowl with plastic wrap directly on the ganache surface to prevent a skin, then refrigerate for 2-3 hours until firm enough to roll.

Scoop out portions of the chilled ganache and quickly roll them into smooth balls between your palms, returning to the fridge if they soften too much.

For cocoa/powdered sugar coating, roll each truffle in a shallow dish until evenly coated.

For melted chocolate coating, dip each truffle using a fork into slowly melted chocolate, tap off excess, and place on parchment paper; add toppings like nuts or freeze-dried raspberries if desired before chocolate sets.

Return the coated truffles to the refrigerator for at least 30 minutes to ensure they firm up completely for serving or storage.