Preheat oven to 170°C. For the chocolate slices with fruit skewer, mix flour, baking powder, sugar, vanilla sugar and cocoa in a bowl. Finely puree mango with a hand blender and add to the dry ingredients together with the buttermilk. Pour the mixture into a coated square baking dish and bake in a preheated oven for about 20 minutes. Leave to cool and cut into cubes.For the fruit layer, puree mango with a hand blender.For the skewers, cut carambola into slices and mango into cubes. Alternate carambola, mango and strawberries on a skewer or, if available, a piece of lemongrass.To serve, apply a little fruit mirror per plate, put a chocolate slice on each and garnish with the fruit skewer.