01 - Place finely chopped white chocolate in a medium heatproof bowl.
02 - In a small saucepan, gently heat heavy cream and unsalted butter over medium heat until the mixture comes to a simmer.
03 - Pour hot cream and butter over the white chocolate. Allow to sit for 2 minutes, then stir with a spatula or whisk until the mixture is smooth and glossy.
04 - Stir in vanilla extract and a pinch of salt, ensuring the mixture is fully blended.
05 - Evenly divide the mixture into three separate bowls. Add red food coloring and fold in crushed freeze-dried raspberries to one bowl, blue food coloring and crushed freeze-dried blueberries to another, and leave the third bowl plain.
06 - Cover and refrigerate all three bowls for about 45 minutes or until the mixtures are firm enough to scoop.
07 - Scoop 1/2 teaspoon from each colored mixture. Gently press one portion of each color together and roll between your palms to form a tricolor ball. Repeat with remaining mixture.
08 - Roll each ball in white nonpareil sprinkles or sanding sugar for festive decoration. Arrange on a parchment-lined baking sheet.
09 - Refrigerate truffles for an additional 20 minutes to ensure they are set before serving.