Preheat oven to 350 degrees. Spray a 13 by 9-inch baking dish with cooking spray, set aside. In a medium mixing bowl whisk together flour, ginger, cinnamon, nutmeg, cloves, baking soda and salt for 20 seconds, set aside.
In the bowl of an electric stand mixer fitted with the paddle attachment, blend together butter, brown sugar and molasses until combined. Mix in egg an vanilla extract. With mixer set on low speed slowly add in flour mixture and mix until combined. Fold batter with a spatula as needed until batter appears to be evenly incorporated.
Pour dough into prepared baking dish and spread and press into an even layer using your hands. Bake in preheated oven until bars have baked through, about 14 – 17 minutes (be careful not to over-bake). Transfer baking dish to a wire rack and let bars cool completely.
For the cream cheese frosting: In the bowl of an electric stand mixer fitted with the paddle attachment cream together butter and cream cheese until smooth. Add in powdered sugar and vanilla and mix until light and fluffy. From here I like to freeze the frosting in 3 minute intervals then I mix between intervals using the stand mixer until it’s the consistency I like (it usually takes about 9 minutes total). Spread frosting over cooled bars. Cut into squares. Cover with lid or plastic wrap and store in refrigerator.