Add the dark chocolate to a microwave-safe bowl and melt the chocolate using a microwave in 30-second intervals, stirring after each interval until the chocolate is completely melted and no lumps remain. Cover the bowl with plastic wrap and let the chocolate slightly cool.

Meanwhile, add the white rice flour, tapioca flour, brown rice flour, xanthan gum, cocoa powder, baking powder, and salt to a bowl and whisk together until combined.

Then, in a separate bowl, add the unsalted butter, brown sugar, and granulated sugar and beat, at medium-high speed, using a handheld mixer or standalone mixer fitted with the paddle attached until light and fluffy (2-3 minutes). Next, add the eggs and vanilla extract and beat until creamy (1-2 minutes). Now pour the melted chocolate and beat until combined (1-2 minutes).

Afterward, add the flour mixture and beat until combined (1-2 minutes). Then add the chocolate chips and mix them into the cookie dough using a spatula.

Transfer the cookie dough to the fridge and let it chill for 30 minutes.

Preheat the oven to 180°C (356°F) while the cookie dough chills.

Roll a 1 ½ tablespoon of cookie dough into a ball and place each ball on a baking tray aligned with parchment paper at least 6 cm (~2.5 inches) apart. Bake the cookies for 10-12 minutes or until the edges are set.

Allow the cookies to cool on the baking tray for 5 minutes before transferring them to a cooling rack.