1 cup chocolate chunks or chips (dairy-free, soy-free if necessary)
Preheat the oven to 325 degrees F. Line two baking sheets with parchment paper.
Combine the flour mix, cocoa powder, xanthan gum, baking soda, cream of tartar, and salt. Mix thoroughly, being sure to work out any lumps of cocoa powder.
In the bowl of a stand mixer fitted with the paddle attachment, combine the canola oil and milk, mixing on medium speed for 30 seconds. Add the vanilla and sugar. Mix for 20 seconds.
Add the dry ingredients to the wet and mix on low speed, scraping down the sides of the bowl. Fold in the chocolate chunks.
Scoop out the dough by heaping tablespoons and place on the baking sheets, 12 per sheet. Wet your hands with a little water and roll the dough into balls, moistening your hands again as necessary. (I just used the smallest Pampered Chef cookie scoop, and it worked well).
Bake in the center of the oven for 12 minutes, until just set. Do not overcook, as chocolate burns easily. You want the inside to remain chewy, not dry.
Let the cookies cool for 5 minutes on the baking sheets before transferring to a cooling rack.
NOTE: This is the "all purpose" flour mix I've been using lately, with really good results.[br] Cybele Pascal's Basic Gluten-Free Flour Mix[br] 4 cups superfine brown rice flour[br] 1 1/3 cups potato starch (not flour)[br] 2/3 cup tapioca starch[br] Combine all ingredients in a large zipper-top bag. Shake until well blended.[br] Source: The Allergen-Free Baker's Handbook by Cybele Pascal
Recipe by The Baking Beauties at http://www.thebakingbeauties.com/2010/07/double-choco-chunk-cookies.html