To make the base: Combine the crushed Weetabix, sugar, baking powder, melted butter, coconut, flour and cocoa. Mix well. Press the mixture into a tin and bake in preheated oven for 15 minutes.
To make the topping: Dissolve gelatine in boiling water. Add sugar, vanilla extract and food colouring (if using). Beat until thick and fluffy. Cool. Pour over the base whilst still warm. Sprinkle with sugar strands or desiccated coconut.