Preheat the oven to 190°C.
Mix together the flour, sugar, baking powder and half of the egg. Using your fingers combine to crumbly dough. Add more egg if necessary. Add the vanilla extract.
Carefully blend the berries with the potato starch and sugar until evenly mixed. Place the berries in the forms, add the topping and pour over the melted butter. Bake in the oven for about 30—35 min until golden brown. Leave to cool slightly and serve with vanilla ice cream or thick yoghurt.