01 -
In a medium-sized mixing bowl, whisk together the all-purpose flour, espresso powder, baking soda, baking powder, and kosher salt.
02 -
Using a stand mixer or handheld mixer on medium-high speed, beat the softened butter, dark brown sugar, and granulated sugar for 1½ to 2 minutes until fully incorporated.
03 -
Add the whole egg, egg yolk, and vanilla extract to the butter mixture. Mix until no yellow streaks remain.
04 -
Gradually add half of the dry ingredient mixture, mixing just until combined. Repeat with the remaining dry mixture.
05 -
Gently fold in the semi-sweet chocolate chunks and dark chocolate chips until evenly distributed. Cover and chill the dough in the refrigerator for 30 minutes.
06 -
Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
07 -
Use a 1½-tablespoon cookie scoop to portion the dough, spacing cookies 2 inches apart on the prepared baking sheets. Bake for 10-12 minutes.
08 -
Allow the cookies to rest on the baking sheet for 2-3 minutes before transferring them to a cooling rack.