Preheat oven to 350 degrees. In a mixing bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, nutmeg and ginger, set aside. In a separate large mixing bowl, using an electric hand mixer, blend together light-brown sugar, granulated sugar, melted butter and applesauce until well combine.
Fluffy Cream Cheese Frosting
Add eggs and vanilla extract and mix until well blended, then add pumpkin and mix until well blended. Add dry mixture and mix just until combine. Pour and spread mixture evenly into a buttered 13 x 9 inch baking dish and bake in preheated oven about 35 - 38 minutes until toothpick inserted into center of cake comes out with a few moist crumbs attached.
Allow bars to cool completely (I covered the baking dish after 15 minutes of cooling to seal in moisture) then cut into bars and frost with Fluffy Cream Cheese Frosting (alternately you can frost bars first then cut into squares) and dust lightly with optional cinnamon and garnish with optional pecans.
In a large mixing bowl, using and electric hand mixer, whip together butter and cream cheese on medium speed until very light and fluffy, about 3 -4 minutes. Mix in vanilla. Add powdered sugar and mix until well blended and smooth.