Begin by measuring out 2 cups of freeze-dried raspberries. Place them in a food processor and pulse until they transform into a fine powder. Set aside for later use.
In a double boiler or a microwave-safe bowl, melt the chopped white chocolate over low heat. If using a microwave, heat in 30-second intervals, stirring in between, until fully melted and smooth. Be careful not to overheat, as white chocolate can easily scorch.
Once the white chocolate is melted, add the room-temperature unsalted butter and heavy cream. Stir the mixture until it is fully combined and silky smooth. This is your truffle ganache.
Add the raspberry powder to the ganache mixture and stir well to combine. The vibrant color should blend beautifully into the creamy chocolate. If the mixture seems too thin, allow it to cool and thicken slightly.
Gradually add the powdered sugar to the ganache, mixing until fully incorporated. Taste the mixture and adjust the sweetness if desired. Once it reaches the perfect balance, set it aside to cool at room temperature for about 30 minutes.
Once the ganache has cooled and thickened, use a spoon or small cookie scoop to portion out small amounts of the mixture. Roll them into balls using your hands. Place each truffle on a baking sheet lined with parchment paper.
Transfer the baking sheet to the refrigerator and chill the truffles for at least 1 hour, or until they are firm.
After chilling, roll the truffles in additional raspberry powder or even some extra melted white chocolate for a beautiful finish. Serve immediately or store for later enjoyment.