01 - Place the finely chopped white chocolate in a heatproof mixing bowl.
02 - In a small saucepan over medium heat, heat the heavy cream and butter until the mixture just begins to simmer.
03 - Immediately pour the hot cream and butter mixture over the white chocolate. Allow to sit for 2 minutes, then stir thoroughly with a rubber spatula until completely smooth and glossy.
04 - Mix vanilla extract and a pinch of salt into the chocolate base until evenly combined.
05 - Divide the truffle mixture into three separate bowls. Tint one portion with red gel coloring and fold in the crushed freeze-dried raspberries. Tint the second portion with blue gel coloring and fold in the crushed freeze-dried blueberries. Leave the third portion plain for the white layer.
06 - Cover and refrigerate each bowl for approximately 45 minutes, or until firm enough to scoop.
07 - Using a truffle scoop or teaspoon, take about 1/2 teaspoon of each colored mixture. Press the three portions together and gently roll between your palms to form a tricolor sphere. Repeat until all mixtures are used.
08 - Roll each truffle gently in white nonpareil sprinkles or sanding sugar to coat evenly.
09 - Place truffles onto a baking sheet lined with parchment paper and refrigerate for 20 minutes to set before serving.