Buttermilk Biscuits

Originally from recipezaar.com
1/2 cup potato starch
3/4 cup cornstarch
1 3/4 teaspoons xanthan gum
1 tablespoon baking powder
1/4 teaspoon baking soda
1/2 teaspoon salt
1 tablespoon sugar
1/3 cup cold butter, cut into 1/4-inch cubes
3/4 cup buttermilk
Directions
1Preheat the oven to 375°F Spray a baking sheet (preferrably a baking stone) with cooking spray.
2Place the starches, xanthan gum, baking powder, baking soda, salt, and sugar into the bowl of a food processor. Process with six 1-second pulses.
3Sprinkle the butter cubes evenly over the flour mixture, cover, and process with 12 1-second pulses. The mixture should resemble coarse crumbs.
4Pour the buttermilk evenly over the mixture. Process for 8 1-second pulses, or until the dough gathers into a moist clump.
5Using your bare hands, quickly gather a clump of dough, lightly form it into a biscuit shape, and drop it onto the cookie sheet. Repeat this for all the remaining dough, trying to handle the dough as little as possible (it's sticky). I usually make 6-8 biscuits.
6Bake 10-12 minutes or until lightly browned.