Preheat oven to 375, and lightly grease two cookie sheets. Cream butter and sugar/brown sugar until light and fluffy. Add eggs and vanilla and stir until blended. In a separate bowl, combine flours, xanthan gum, baking soda, and salt. Gradually add to wet mixture, and stir until combined. Incorporate chocolate chips.
Drop tablespoon-sized spoonful s onto cookie sheets, and bake for 9-11 minutes, until golden. (Time may vary depending on oven and size of cookies, so watch carefully!).