Process berries in a blender or food processor until smooth. Strain mixture into a small bowl and discard seeds. Add sugar and liqueur; stir until sugar dissolves.

Warm 1/4 cup cream and white chocolate in a heavy saucepan over low heat, stirring constantly, until chocolate melts; let mixture cool until lukewarm. Stir in 1 tablespoon raspberry sauce and food coloring. Transfer to a large bowl.

Beat 1 1/2 cups cream in a chilled glass or metal bowl with an electric mixer until soft peaks form; fold into melted chocolate mixture, 1/3 at a time, until no streaks remain.