Add the granulated sugar and orange zest to the bowl of a stand mixer. Using your fingers, rub the zest into the sugar until it resembles damp sand and smells fragrant. Add the softened butter, then beat with the paddle attachment until the mixture is light and airy.

Scrape down the sides of the bowl and add the vanilla, instant coffee, salt, flour, and cocoa powder. Mix until the dough just begins to come together. Add your mix-ins and continue mixing until the dough forms.

Divide the dough in half and transfer each portion to a sheet of plastic wrap. Shape into logs about 3 inches wide and 12 inches long. Wrap tightly and refrigerate for at least 1 hour, or until firm.

Preheat the oven to 350°F. Line a baking sheet with parchment paper.

Remove the dough from the refrigerator and slice into rounds about ¾–1 inch thick. Arrange on the prepared baking sheet and bake for 15–17 minutes. Let the cookies cool slightly on the tray before transferring to a wire rack to finish cooling.