Preheat oven to 350 degrees F and line your baking pans with parchment paper.
Using a food processor or coffee grinder, quickly pulse the oats to form smaller flakes, but not too much, or you will have flour.
In the bowl of a stand mixer, combine the pulsed oats, sorghum flour, brown rice flour, tapioca starch, xanthan gum, baking soda, ground cinnamon, and salt.
In a separate bowl, whisk together the canola oil, sugars, vanilla, and eggs.
With the mixer running on slow speed, add the wet ingredients to the dry ingredients. Mix until combined. Add the chocolate chips and mix until evenly distributed.
Scoop 2 teaspoons of dough on your baking sheet, leaving 3-inches between cookies to allow for them to expand while baking. Dampen your hands with a small amount of water and roll the scooped dough into a smooth ball. This will give your finished cookies a nice round shape.
Bake cookies in preheated oven for 10-12 minutes, decreasing for a chewier cookie, increasing for a crispier cookie. Allow cookies to cool for a few minutes before moving them to a wire rack to cool completely. Store cookies in an airtight container.
If your dough is still too soft, or you want a slightly 'puffy' cookie, add an additional 1/2 cup brown rice flour.
Recipe by Faithfully Gluten Free at http://www.faithfullyglutenfree.com/2012/11/chewy-gluten-free-oatmeal-chocolate-chip-cookies.html