Preheat oven to 350 degrees F. Line 20 muffin cups with muffin liners. Set aside.
In a large bowl, combine the cake mix, eggs, milk, oil, dry pudding mix and spices with a handheld electric mixer for about 2 minutes or until combined. Portion the batter evenly among the muffin cups, filling about 3/4 full. Bake for approx. 15-18 minutes or until a toothpick inserted near the center comes out clean or with moist, not wet, crumbs. Cool completely.
To make the frosting: In the bowl of a stand mixer, cream together the butter, brown sugar and vanilla until creamy, about 1 minute. Add in the spices and gradually add in the powdered sugar, about one cup at a time, until frosting is light and fluffy. Use the heavy cream to stream into the frosting to thin it out if it's too thick. You may not use all of the cream.
Pipe the frosting onto the cooled cupcakes and garnish with a ginger cookie piece, if using.