Line the base of a small tin with baking paper. Place the diced beetroot, coconut, cashews and plum powder in a food processor and process until a breadcrumb consistency is reached. Add the dates, vanilla and coconut oil and mix again until incorporated. Spread the mixture in the base of the tin and press down firmly to create a nice even layer. Set in the fridge.
Combine the melted white chocolate with the coconut oil and stir to combine. Drizzle the white chocolate all over the slice before leaving to set until firm in the fridge for 2+ hours.