Directions

1. Chop chocolate into 1/4-inch chunks; set aside. In a medium bowl, sift together flour, ground ginger, cinnamon, cloves, nutmeg, and cocoa.
2. In the bowl of an electric mixer, fitted with the paddle attachment, beat butter and grated ginger until whitened, about 4 minutes. Add brown sugar; beat until combined. Add molasses; beat until combined.
3. In a small bowl, dissolve baking soda in 1 1/2 teaspoons boiling water. Beat half of flour mixture into butter mixture. Beat in baking-soda mixture, then remaining half of flour mixture. Mix in chocolate; turn out onto a piece of plastic wrap. Pat dough out to about 1 inch thick; seal with plastic wrap; refrigerate until firm, at least 2 hours.
4. Preheat oven to 325 degrees. Line two baking sheets with parchment paper or nonstick baking mats. Roll dough into 2-inch balls; place 2 1/2 inches apart on baking sheets. Refrigerate 20 minutes. Roll dough balls in granulated sugar and return to baking sheets. Transfer to oven and bake until surfaces crack slightly, about 18 minutes. Let cool 5 minutes; transfer to a wire rack to cool completely.