01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the gluten-free flour, baking soda, salt, and espresso powder until well combined.
03 - In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar until the mixture is light and fluffy, approximately 2 minutes.
04 - Add the egg and vanilla extract to the butter mixture, mixing until fully incorporated.
05 - Gradually add the dry ingredients to the wet mixture. Mix on low speed until just combined, being careful not to overmix.
06 - Fold the toasted pecans and chocolate chunks into the dough using a spatula.
07 - Scoop tablespoon-sized mounds of dough onto the prepared baking sheets, leaving about 2 inches of space between each cookie.
08 - Bake for 10 to 12 minutes, or until the edges are golden brown and the centers appear set.
09 - Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.