Preheat oven to 350˚F. Line 2 baking sheets with parchment paper; set aside.
In large bowl, beat butter with granulated sugar and brown sugar until fluffy; beat in egg and molasses until combined. In separate bowl, whisk together flour, cocoa, ground ginger, cinnamon, baking soda, cloves, salt; stir into butter mixture just until combined. Add semi-sweet chocolate and combine.
Place coarse sugar in shallow dish. Roll dough, 1 tbsp at a time, into balls; roll in sugar to coat. Arrange 2 in. (5 cm.) apart on prepared pans. Bake, 1 sheet at a time, just until edges are firm, 10 to 12 minutes.
Bang tray on counter to level, then let cool on pans for 5 minutes. Transfer to racks; let cool completely.
Notes
Tip: The trick to good molasses cookies is not overbaking them –underbaking is ideal.