Preheat the oven to 350 degrees F (175degrees C).
In a medium bowl, mix together the butter and vanilla until well blended. Sift in the icing sugar, rice flour, cornstarch and tapioca flour. Stir into the butter mixture until all of the dry ingredients have been absorbed. Mix in the ground hazelnuts and chopped hazelnuts. Add a little water until the consistency is right for dropping.
Drop by spoonfuls onto a lightly greased baking sheet. Bake for 8 to 10 minutes. Cool on a wire rack and store in a closed container.
