Preheat oven to 325 degrees. Line a baking sheet with parchment paper (use two baking sheets if desired).
Whisk together flour, cocoa, baking powder, baking soda and salt in a medium bowl.
Mix together brown sugar, eggs, and vanilla in a separate bowl.
Melt unsweetened chocolate and butter in a saucepan and heat over medium heat – stirring frequently.
Add the melted chocolate mixture into the eggs/sugar mixture until well combined.
Fold in the flour mixture until no dry ingredients remain.
Refrigerate dough for 15 minutes.
Place the granulated sugar and Espresso Sugar into separate bowls.
Once the dough is chilled – use 2 tablespoons dough at a time (about a medium cookie scoop), roll dough into a ball. Roll in granulated sugar until coated. Then roll in espresso sugar until well coated (you may have to roll the dough in your hands again after the first sugar before dropping into the espresso sugar.) Coat evenly with espresso sugar.
Space the dough balls on the prepared baking sheets.
Bake for 12 minutes until cookies are puffy and cracked – NOTE the cookies will appear uncooked in the center and in the cracks.
Cool completely before serving.