Preheat oven to 350º
grease an 8x8 baking pan and line with parchment paper, set aside
Combine flour, baking powder, salt, and spices in a mixing bowl and set aside
In a separate bowl, beat butter, brown sugar, and molasses together until well blended
Stir in dry ingredients until all is incorporated
Press into prepared 8x8 baking pan, and bake for about 18 minutes, until bars are set and appear dry on top
Remove from oven, use parchment to life out of the pan and place on a wire rack, and let cool completely
make the frosting by beating together the cream cheese, butter, and powdered sugar until smooth
drizzle in enough vanilla to make a spreadable frosting, and add a little milk if needed to make the frosting spreadable
spread on completely cooled bars, add sprinkles if desired
cut into bars