Preheat your oven to 350°F (175°C).
In a large mixing bowl, add the softened butter and granulated sugar. Beat together until light and fluffy, about 2-3 minutes.
Add in the egg and vanilla extract. Beat until fully incorporated.
In a separate bowl, whisk together the flour, cocoa powder, baking powder, Kosher salt, and espresso powder.
Gradually add the dry mixture to the wet ingredients, mixing on low speed until just combined.
Using a cookie scoop, place the dough onto a baking sheet lined with parchment paper.
Bake for 10-12 minutes, or until edges are set and centers are still soft.
Let cool on the baking sheet for about 5 minutes before transferring to a cooling rack.
