Preheat oven to 350°F (175°C) and grease and flour a 9x13 inch baking pan.
In a large bowl, whisk together the gluten-free flour, cocoa powder, granulated sugar, brown sugar, baking soda, and salt.
Add the vegetable oil, eggs, and vanilla extract to the dry ingredients and mix well.
Gradually add the boiling water to the batter and mix until smooth. The batter will be thin.
Stir in the chocolate chips.
Pour the batter into the prepared baking pan and spread evenly.
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with moist crumbs attached. Let cool completely before frosting and adding sprinkles.
Notes
For best results, let the brownies cool completely before cutting. Store in an airtight container at room temperature.