Ingredients:
- 1 cup confectioners’ sugar, plus more for finishing cookies
- 14 tbsp. unsalted butter, softened
- 2 tsp. vanilla extract
- 6 oz. walnuts or almonds, finely ground in food processor
- 1 1⁄4 cups plus 2 tbsp. tapioca flour
- 1⁄2 cup chickpea flour
- 1⁄3 cup chestnut flour
- 1⁄4 cup white rice flour
- 1⁄2 tsp. fine salt