Melt the unsalted butter in a medium saucepan over medium heat, stirring frequently until it turns golden brown and develops a nutty aroma, about 5-7 minutes. Remove from heat and let cool slightly.

In a separate bowl, whisk together the gluten-free flour blend, baking soda, and salt. Set aside.

In a large mixing bowl, combine the packed brown sugar and granulated sugar. Pour the slightly cooled brown butter over the sugars and mix until well combined. Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

Gradually add the dry mixture to the wet mixture, stirring gently until just combined. Fold in the semi-sweet chocolate chips.

Chill the dough for at least 30 minutes for chewier cookies.

Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper. Drop rounded balls of dough onto the prepared baking sheet, spacing them about 2 inches apart. Bake for 10-12 minutes until the edges are golden and the centers are set. Let cool on the baking sheet for 5 minutes before transferring to a wire rack.