Prepare the Raspberry Infused Cream: Gently heat the heavy cream in a saucepan over medium heat until it just begins to simmer. Remove from heat. Stir in the ground freeze-dried raspberries and let steep for 15-20 minutes to infuse the cream with raspberry flavor. Strain the cream through a fine-mesh sieve, pressing on the solids to extract as much flavor as possible. Discard the solids.

Make the Ganache: Place the chopped chocolate in a heat-safe bowl. Reheat the raspberry infused cream until it is hot but not boiling. Pour the hot cream over the chocolate and let it sit for 1 minute to allow the heat to melt the chocolate.

Emulsify: Gently whisk the chocolate and cream together, starting from the center of the bowl and working your way outwards, until the mixture is smooth and glossy. Be careful not to over-whisk, as this can cause the ganache to separate.

Add Flavor and Fat: Stir in the softened butter and raspberry liqueur (if using) until fully incorporated. The ganache should be smooth, shiny, and have a beautiful deep color.

Chill: Cover the bowl with plastic wrap, pressing it directly onto the surface of the ganache to prevent a skin from forming. Refrigerate for at least 4 hours, or preferably overnight, until the ganache is firm enough to scoop.

Shape the Truffles: Once the ganache is firm, use a small spoon or melon baller to scoop out portions of the ganache. Roll each portion between your palms to form a ball. Don't worry if they aren't perfectly round at this stage.

Chill Again: Place the formed truffles on a parchment-lined baking sheet and refrigerate for another 30 minutes to firm them up further. This will make them easier to coat.

Coat the Truffles: Place your chosen coating (cocoa powder, chopped nuts, raspberry powder) in a shallow dish. Roll each truffle in the coating until it is evenly covered.

Final Chill: Return the coated truffles to the refrigerator for at least 15 minutes to allow the coating to set.

Serve and Enjoy: Serve the truffles chilled or at room temperature.