1 ½ cup gluten-free flour
¼ cup sweet rice flour
1 teaspoon xanthan gum
½ teaspoon baking soda
½ teaspoon gluten-free baking powder
1/8 teaspoon salt
1 stick unsalted butter, room temperature
1 cup sugar
2 teaspoon grated orange zest
1 teaspoon vanilla
1 ½ cup chopped toasted walnuts
Mix together gluten-free flour, sweet rice flour, xanthan gum, baking soda, baking powder and salt.
Cream the butter until white. Add the sugar and beat until fluffy, about 5 minutes. Blend in the eggs, one at a time. Add the orange zest and vanilla, then stir in the nuts. Slowly incorporate the dry ingredients to form a soft dough. Refrigerate the dough for at least one hour or overnight.
Preheat the oven to 375F. Lightly grease 2 cookie sheets and line with parchment paper.
Divide the dough into 3 equal pieces. Roll each piece into a log 1 ½ to 2 inches thick. Place 2 logs on one sheet, and one log on the other sheet, leaving enough space between them for the dough to spread while baking. Bake the logs for 20 minutes.
Remove the cookie sheet from the oven and let sit for 5 to 10 minutes. Slice the logs on a slight diagonal about ¾ inch thick. Place the slices, cut side down, on the cookie sheets. Lower the oven temperature to 350F and bake the slices for 10 to 12 minutes. Cool on a cooling rack. Store in an airtight container.