Start by taking butter out of the fridge about an hour before baking – you want it soft enough that your finger leaves an indent when you press it, but not so warm that it’s starting to melt or look greasy.
Preheat your oven to 350°F and line two baking sheets with parchment paper.
In a large bowl, cream together the softened butter, granulated sugar, and brown sugar. I use an electric mixer on medium speed for about 3-4 minutes until it’s really light and fluffy.
Add the eggs one at a time, beating well after each one. Then mix in the vanilla extract.
In a separate bowl, whisk together the flour, cocoa powder, espresso powder, baking soda, and salt.
Gradually add the dry ingredients to your wet mixture, mixing on low speed just until combined. The dough will be quite thick and look almost like brownie batter.
Stir in the chocolate chips by hand using a wooden spoon or spatula. The dough will be pretty stiff at this point – that’s exactly what you want.
Scoop rounded tablespoons of dough onto your lined baking sheets, leaving about 2 inches between each cookie. They’ll spread a bit while baking.
Bake for 11-13 minutes, rotating the pans halfway through.
Let them cool on the baking sheets for 5 minutes – during this time they’ll settle and get those lovely crackly tops. Then transfer them to a wire rack to cool completely.