Whisk together the dry ingredients, spices, and the sugar.
Add the remaining ingredients and mix until combined.
For thicker bars, press the batter into an even layer in a 9x13 baking dish. For thinner bars, press the batter into an even layer on a standard sized half sheet pan, about 17x12. It will not reach the edges but should be about 3/4 of an inch thick.
For a 9x13 pan, bake for 25-30 minutes. For a sheet pan, bake for 15-20 minutes. In both cases, a toothpick should come out clean.
Let cool and then ice with cream cheese frosting.
For the Cream Cheese Frosting
Whisk together the cream cheese and butter.
Add the powdered sugar, vanilla, and cream.
Whisk until light and fluffy and easily spreadable.