01 -
On medium heat, cook butter in a metal pan until the solids turn golden brown (takes around 10 minutes). Scrape everything, including the browned bits, into a bowl.
02 -
Add the espresso grounds to the butter and let it rest until it cools, about 20–30 minutes.
03 -
Add both sugars to the cooled butter mixture and whisk vigorously for a minute so it blends well.
04 -
Stir in the vanilla, egg, and yolk until the texture is smooth.
05 -
Carefully mix the flour, salt, baking soda, and chocolate chunks just enough to bring the dough together.
06 -
Scoop the dough onto a baking sheet lined with parchment, then freeze for a minimum of 3–4 hours—or overnight if you can.
07 -
Warm up your oven to 350°F/180°C. Bake the frozen cookies for 10–12 minutes, leaving 2 inches between each. Edges should look golden while the centers stay soft.
08 -
Place the baked cookies on a wire rack to cool right on their baking sheet.