1. Preheat the oven to 325°F. On a large plate, combine the sugar, cocoa, gingers, and chocolate and mix. Set aside. 2. Cut the log into twenty 1/2-inch rounds. Firmly press one cut surface of each round into the cocoa mixture and arrange the rounds 2 inches apart on all sides on a parchment-lined or nonstick cookie sheet or sheets. 3. Bake until golden brown, 15 to 20 minutes. Remove the cookies with a spatula and cool on a wire rack.