Combine granulated sugar, brown sugar, and vegetable oil in a large mixing bowl. Mix well. Add eggs one at a time, mixing thoroughly after each addition. Stir in vanilla extract.

In a separate bowl, whisk together gluten-free flour, cocoa powder, baking powder, and salt. Gradually add to the wet mixture, stirring gently until just combined.

Cover the dough and chill in the refrigerator for 30 minutes.

Preheat oven to 350°F. Roll chilled dough into tablespoon-sized balls and coat in powdered sugar. Place on a lined baking sheet with 2 inches of space between each.

Bake for 10-12 minutes until edges are set and tops are crinkled. Let cool on the baking sheet for a few minutes before transferring to a wire rack.