Finely crush the freeze-dried raspberries using a food processor or mortar and pestle until powdered.

In a heatproof bowl, combine the chopped white chocolate and softened unsalted butter.

Heat the heavy whipping cream in a small saucepan over medium heat until simmering, then pour it over the chocolate mixture.

Let it sit for about 5 minutes to melt, then whisk until it transforms into a creamy, smooth ganache.

Gradually add the raspberry powder into the ganache, blending until evenly distributed.

Cover the bowl with plastic wrap and refrigerate for approximately 2 hours until hardened.

Line a baking sheet with parchment paper to prevent sticking, then roll each portion of ganache into small balls.

Freeze the truffles for 30-45 minutes to firm them up before coating.

Melt the bittersweet chocolate in a double boiler, stirring gently until smooth and cooled to 85-90°F.

Dip each ganache ball into the melted chocolate using a fork and sprinkle with reserved raspberry powder.

Allow them to set at room temperature for about 1 hour, or refrigerate for 15 minutes.