Heat a small pot over medium heat, add fresh blueberries or blueberry powder, and mix with full-fat cream and unsalted butter. Simmer for about 2 minutes.

Use an immersion blender to puree the blueberry mixture until completely smooth. Set aside to cool slightly.

Melt the white chocolate chips in a double boiler over low heat until glossy.

Gradually mix the blueberry mixture into the melted chocolate until combined.

Transfer the ganache mixture to a sealed container and refrigerate for 2 to 3 hours.

Roll chilled mixture into smooth balls about 1 inch in diameter.

Roll each truffle in powdered sugar until fully coated.

Store truffles in an airtight container in the refrigerator for up to a week or freeze for longer storage.