Preheat oven to 175°C (350°F) and line baking trays.
Cream butter and sugar until pale and fluffy. Beat in the egg and vanilla.
Fold in flour and salt until a soft dough forms. Chill for 30 minutes to an hour.
Roll out the dough onto a lightly floured surface. Cut out your shapes using your cookie cutters (I used a fluted cookie cutter and the end of a piping nozzle to make the small holes for a frilled effect).
Bake 10-12 minutes. Cool completely.
Make your raspberry purée - using a hand mixer, blend some raspberries. Pass the mixture through a sieve if you don't want seeds.
Make ganache: heat cream, pour over chopped white chocolate, stir until smooth. Add raspberry purée, chill slightly to thicken.
Sandwich cookies with ganache and decorate as desired.