Whisk the flour, cocoa powder, baking soda, ginger, cinnamon, cloves, nutmeg, and salt together in a medium bowl until combined. Set aside.

In a large bowl using a handheld or stand mixer fitted with a paddle attachment, beat the butter and brown sugar together on high speed until creamy and combined, about 3 minutes. (Here’s a helpful tutorial if you need guidance on how to cream butter and sugar.) Add the molasses, egg, and vanilla extract and beat until combined, about 1 minute. Scrape down the sides and up the bottom of the bowl and beat again as needed to combine. The mixture may look a bit curdled; that’s ok.

Add the dry ingredients to the wet ingredients and mix on low until combined. Dough will be thick and sticky. Cover dough tightly and chill in the refrigerator for at least 2 hours and up to 3 days. Chilling is imperative for this sticky cookie dough.

Preheat oven to 350°F (177°C). Line large baking sheets with parchment paper or silicone baking mats. Set aside.

Remove cookie dough from the refrigerator. If the cookie dough chilled longer than 2 hours, let it sit at room temperature for 10 minutes. The cookies may not spread in the oven if the dough is that cold. Roll cookie dough into balls, about 1.5 Tablespoons (30g) of dough each (I use this medium cookie scoop). Roll each in granulated sugar and arrange 3 inches apart on the baking sheets.

Bake cookies for 12 minutes or until edges appear set.

Remove from the oven and allow cookies to cool on the baking sheet for 10 minutes before transferring to a cooling rack to cool completely.

When the cookies are cooled, melt the chopped chocolate, either in a double boiler or use the microwave. Microwave in 20-second increments, stirring after each until completely melted. Dip half of each cooled cookie into the chocolate, and use any leftover chocolate to drizzle on top, if desired. Sprinkle chopped crystallized ginger on chocolate.

Allow chocolate to completely set at room temperature or in the refrigerator.

Cover leftover cookies tightly and store at room temperature for up to 1 week.