01 -
Melt butter in a stainless steel pan over medium heat until golden brown bits form (around 10 minutes). Pour the butter and all browned solids into a mixing bowl.
02 -
Add in espresso powder, then let the butter-coffee mixture come to room temp (about 20-30 minutes).
03 -
Mix the cooled butter with both sugars for a minute or so until everything’s combined nicely.
04 -
Whisk in the egg, vanilla, and the yolk until smooth and creamy.
05 -
Lightly mix the flour, soda, salt, and chocolate pieces into the wet mixture. Don't overdo it.
06 -
Use a cookie scoop to portion dough onto parchment paper-lined trays. Freeze for at least 3-4 hours or overnight for better results.
07 -
Set your oven to 350°F (180°C). Place the frozen dough balls 2 inches apart on a tray and bake for 10-12 minutes, until the edges are golden but the centers are still soft.
08 -
Place the baked cookies on the tray and let them cool completely on a wire rack.