Preheat your oven to 350°F (175°C).

In a mixing bowl, combine all-purpose flour, cocoa powder, granulated sugar, brown sugar, instant espresso powder, baking soda, and salt. Whisk until well blended.

In a separate bowl, whisk the melted butter, vanilla extract, and egg white together until smooth.

Gradually add the dry ingredients to the wet mixture, stirring until fully incorporated.

Using a cookie scoop, portion out the dough into small balls and roll each in additional granulated sugar.

Place the cookie balls on a parchment-lined baking sheet and bake for 8-10 minutes.

Allow the cookies to cool on the baking sheet for a few minutes, then transfer to a wire rack.