⅓cupcocoa powder(half dutch process and special dark)
1ounceGerman sweet baking chocolate
1ouncesemi-sweet baking chocolate
granulated and powdered sugar(for rolling/coating dough)
PREPARE baking sheets by lining with aluminum foil. Do NOT preheat oven before making cookie dough as it needs time to chill before baking.
WHISK together flour, cocoa powder, salt, baking soda, and cornstarch in a medium bowl; set aside. Finely chop (almost shaving) the semi-sweet baking chocolate; set aside. In a small bowl, combine instant coffee and water; stir to dissolve and set aside.
CREAM butter and sugars in a large bowl. Begin on a low speed until the butter and sugars begin to stick together, then turn speed up to medium until there are no more chunks or pieces or butter showing (approximately 3 minutes).
MELT German sweet baking chocolate and mix into butter mixture until fully incorporated. Add in egg, coffee, and vanilla extract and combine.
STIR in flour mixture in ⅓ parts. Add chopped/shaved semi-sweet chocolate with the last of the flour mixture.
CHILL dough for half an hour. Preheat oven to 350ºF. Pour extra granulated sugar and powdered sugar into two separate, shallow bowls.
SCOOP dough into 1-inch balls and roll in hands to make smooth. FIRST roll the dough ball into the granulated sugar, THEN into the powdered sugar, ensuring each ball is completely covered.
BAKE for 10-12 minutes. Let the cookies rest on the baking sheet for 5 minutes before moving to a cooling rack.
Mexican Spiced Variation: Whisk into the flour mixture 1/2 teaspoon each of cayenne pepper, chili powder, and ground cinnamon.