3/4 cup brown rice flour 3/4 cup white rice flour 3/4 cup sorghum flour 1/2 cup tapioca flour 1 1/2 tsp xanthan gum 1 teaspoon baking soda 1/2 teaspoon baking powder , gluten free 1/2 teaspoon salt 1 1/2 cups granulated sugar 3/4 cup unsalted butter, at room temperature 2 oz cream cheese 1 large egg 1/2 teaspoon vanilla extract , gluten free 2 tablespoons fresh lemon juice 1/3 cup granulated sugar, for rolling cookies