Prepare Blueberry Mixture: Heat blueberries, unsalted butter, and cream in a medium saucepan over low heat for about 2 minutes, until the berries soften.

Blend: Use an immersion blender to puree the mixture until smooth, then transfer to a bowl and let it cool slightly.

Melt Chocolate: Melt white chocolate chips in a double boiler over simmering water, stirring frequently until smooth.

Combine Mixtures: Fold the blueberry puree into the melted chocolate until the mixture is a light lavender color.

Chill: Refrigerate the combined mixture for 2-3 hours or overnight until firm.

Form Truffles: Roll chilled mixture into 1-inch balls using hands or a scoop.

Coat: Roll each truffle ball in powdered sugar until covered; let sit to allow coating to adhere.

Store: Keep the truffles in an airtight container in the refrigerator for up to a week.