Raspberry and white chocolate Rice Krispie bars

Method

1. Lightly grease the base and sides of the cake tin and line with baking paper. Melt the butter and marshmallows in a large pan over a low heat until smooth. Add the vanilla extract (if using) and half the white chocolate, stirring until melted and incorporated, then remove from the heat.
2. Stir the puffed rice cereal and freeze-dried raspberries into the marshmallow mixture, making sure everything is well coated, then tip the mixture into the prepared tin. Use a damp hand or lightly oiled spoon to press the mixture into the tin, smoothing the top. Chill until set (about 1 hour).
3. Melt the remaining chocolate in a small bowl over a pan of barely simmering water (or in the microwave on low power in 20 second bursts). Once the cake has set, remove it from the tin, sprinkle with more freeze-dried raspberries and fresh raspberries (if using), then drizzle the melted chocolate over the top. Once the chocolate sets, slice into bars to serve. The bars will keep in an airtight container in the fridge for 3-4 days.