Method :Preheat the oven to 300F. In a bowl, combine the flours, baking powder and salt, mix and set aside. Using a food processor, beat the butter with the erythritol, egg and vanilla. Add dry ingredients to food processor mixture and blend again until combined. On a baking sheet with parchment paper, make balls of cookie dough and press lightly. Lightly wet your thumb to form a hole in the center to put about a teaspoon of hazelnut spread for each cookie. Cook for ten minutes!