Preheat the oven to 350°F (175°C). Grease 18 cups of a regular sized muffin tin with nonstick cooking spray or use muffin liners to prevent sticking. Set aside.
In a medium mixing bowl, combine the gluten-free flour blend, baking soda, and salt. Set aside.
In a separate large mixing bowl, add the room temperature butter, brown sugar and granulated sugar.
Cream with an electric mixer for 2-3 minutes, until light and fluffy, scraping down the sides of the bowl with a spatula as needed.
Add the eggs and vanilla extract to the creamed butter mixture. Mix until smooth.
Add half of the dry ingredients to the butter mixture and stir until just combined. Repeat with the remaining flour mixture, stirring until no more streaks of flour remain.
Stir in the chocolate chips until distributed throughout the cookie dough.
Scoop the dough into 2-3 tablespoon balls and place in each greased muffin well. You should be able to fill about 18 muffin cups.
Bake at 350°F (175°C) for 14-16 minutes, until the edges are golden brown and the center is set. Remove from the oven and let cool for a few minutes.
Then, use a tablespoon or other rounded object to indent the cookie cups in the center while the cookies are still warm. This will give you plenty of room for the frosting.
Allow the cookie cups to cool in the muffin tin for about 10 minutes before transferring them to a wire rack. This helps them set properly and makes removal easier without breaking. Let the cookie cups cool completely before decorating.
Frost with your favorite buttercream once cool and decorate with sprinkles.
Serve and enjoy!