In a medium/small bowl, whisk together the gluten free flour, xanthan gum, baking soda, salt, and baking powder. Stir in the gluten free oats.

Add the melted butter, shortening, and light brown sugar to the bowl of a stand mixer fitted with a paddle attachment. Beat together until smooth.

Add the egg and vanilla extract and mix untillight in color, creamy, and slightly thickened, about 1 minute.

Scrape down the bowl add the flour/oat mixture to the bowl. Mix on medium-low speed until completely combined, scraping down the bowl as necessary. Add the chocolate chips and mix until incorporated.

Cover and refrigerate 6 hours or overnight.

When ready to bake, preheat oven to 350 degrees and line a baking sheet with parchment paper or a silicone baking mat. Use an OXO large scoop to scoop the dough. Roll the dough into balls and slightly flatten to form a puck shape.

Bake in batches of 6-8 cookies at a time on a single sheet on the center rack for 12 minutes. Cool the cookies on the pan for at least 10 minutes before removing from the pan to cool on a wire rack.(The cookies will look under-done when they first come out but will finish baking as they cool on the pan.