01 - Combine raspberries, sugar, and lemon juice in a small saucepan over medium heat. Cook, stirring constantly, until raspberries break down completely and mixture thickens to a syrup-like consistency, approximately 5-7 minutes. Press through a fine-mesh sieve to remove all seeds. Allow to cool to room temperature before proceeding.
02 - Place white chocolate, heavy cream, and butter in a heatproof bowl. Set bowl over a pot of barely simmering water, ensuring bottom does not touch water. Stir continuously until completely melted and emulsified into a smooth, glossy mixture. Remove from heat and whisk in vanilla extract along with 2 tablespoons of cooled raspberry reduction.
03 - Cover the bowl tightly with plastic wrap, pressing directly onto surface to prevent skin formation. Refrigerate for 1-2 hours until mixture is firm enough to hold its shape when scooped but still pliable.
04 - Line a baking sheet with parchment paper. Using a tablespoon or small cookie scoop, portion out chilled ganache into 24 equal pieces. Roll each portion between lightly greased palms to form smooth spheres. Arrange on prepared baking sheet and freeze for 30 minutes to firm completely.
05 - Melt remaining white chocolate in a double boiler until smooth and fluid. Working quickly, drop each frozen truffle center into melted chocolate, using a fork to submerge completely. Lift truffle, tapping fork against bowl edge to remove excess chocolate. Transfer to parchment-lined sheet and immediately sprinkle tops with crushed freeze-dried raspberries while chocolate remains wet.
06 - Refrigerate completed truffles for 20 minutes until chocolate coating is completely set. Transfer to an airtight container separated by wax paper layers. Store refrigerated for up to 2 weeks.