Using a food processor or mini-chopper, puree raspberries until smooth. Gently press mixture through a fine-meshed strainer to remove seeds.

Place raspberry puree in a medium saucepan; stir in the powdered sugar. Place over medium heat and cook, stirring often, until mixture is reduced to ⅔ cup. (Note: The puree will get very thick near the end of cooking; make sure to stir often to prevent it from burning.) Remove raspberry puree from heat and set aside.

Heat the heavy cream in a separate saucepan until hot but not boiling. Pour the heavy cream into a medium mixing bowl. Add the chopped chocolate and stir until chocolate has fully melted. Add raspberry puree, light corn syrup, butter, black pepper and salt; stir until mixture is well combined and smooth. (Note: If some larger chunks of chocolate remain and don’t fully melt, simply place the ganache in a heatproof mixing bowl over a saucepan of gently simmering water until it heats up enough to melt the remaining chocolate.)

Cover bowl with plastic wrap, pressing wrap down so that it touches the surface of the ganache. Refrigerate for at least 2-3 hours, or until hard.

Line a baking tray with wax paper or foil. Using a spoon, scoop ganache into small ¾” balls. Place balls on lined baking tray and freeze for at least 2 hours.

Place 12 oz. of chocolate into a heatproof bowl. Place bowl over a gently simmering saucepan, making sure the bottom of the bowl does not touch the water. Stir chocolate with a rubber spatula often until it melts and reaches 120°F.

Remove the bowl from the saucepan and wipe any condensation off the bottom of the bowl. (Note: It is very important that no water gets in the bowl with the melted chocolate, or the chocolate will seize.)

Gradually add remaining 4 oz. of chopped chocolate to the bowl, stirring after each addition until fully melted and smooth.

Test the temperature of the chocolate. The goal is to let the chocolate cool to 86°F. If the chocolate is above 86°F, continue stirring until it drops to 86°F. (If it is already below 86°F, continue to next step.)

Place the heatproof bowl with the chocolate back over the saucepan with simmering water. Reheat, stirring often, until chocolate reaches 88°-91°F. The goal is to maintain a temperature in this range while you dip the ganache balls (next step). (Tip: Try to work fairly quickly while dipping the balls, and, if necessary, adjust the heat to keep chocolate between 88°-91°F).

Drop each ganache ball into the bowl of melted chocolate. Roll it back and forth until it’s fully coated, and then use a fork to lift the truffle out of the bowl. Allow excess chocolate to drip off and then place truffles back onto lined baking sheet. Set truffles aside until completely cool.

{Optional} After they’ve cooled, drizzle tops of truffles with melted white chocolate.

Store truffles in air-tight container in refrigerator, but allow them to come to room temperature before serving.