Measure and prepare all of your ingredients before starting to ensure a smooth process.
In a large mixing bowl, combine the flour, cocoa powder, cinnamon, ginger, baking soda, cloves, nutmeg, and salt. Whisk the dry ingredients until fully combined and set aside.
In a separate bowl, whisk together the egg, molasses, and vanilla extract until smooth and well blended.
In the bowl of your kitchen mixer, add the room-temperature unsalted butter and packed brown sugar. Using the paddle attachment, cream them together on medium speed for about 2-3 minutes, until the mixture is light and fluffy.
Scrape the butter mixture from the sides of the bowl using a silicone spatula, then add the egg and molasses mixture. Mix on medium speed until fully combined.
Gradually add the dry ingredients to the wet mixture, about ⅓ at a time, mixing on low speed after each addition.
Continue mixing until a smooth, slightly firm dough forms. The dough should hold together but not be sticky.
Divide the dough into two equal portions, flatten them into disks, and wrap in plastic wrap. Place the dough in the refrigerator to chill for at least 1 hour, which helps firm it up, making it easier to roll and cut. At this phase, you can also freeze the dough for up to 3 months – just thaw it in the fridge overnight before using.