Prep: Begin by preheating the oven to 350 degrees. Then, lightly grease the bottom and sides of a jelly-roll pan {15x10x1} with non-stick spray. Set aside.
Batter: Next, in a large bowl, beat together the eggs, sugar, vegetable oil and pumpkin puree until smooth. Then, add in the dry ingredients starting with the flour, baking soda and baking powder, all three spices called for, and lastly the salt. Stir well to combine all the ingredients.
Proceed to pour the batter into the prepared pan and lightly shake it to even out the batter.
Bake: Place the pan in the preheated oven and bake for 25-30 minutes, until light brown and a toothpick inserted in the center comes out clean. Be sure to allow the bars to fully cool before frosting.
Cream Cheese Frosting: In a large bowl, using an electric handheld mixer, combine the cream cheese, butter, powder sugar and vanilla extract, mix until smooth. Spread on top of the bars in a nice even layer, covering the entire surface of the treat. Slice, serve and enjoy!
Alternate topping option- Browned Butter Frosting: In a small saucepan, heat the butter over medium heat, stirring constantly. Cook until butter turns a nice golden brown. It took mine about 5 minutes and when it turned, it turned very suddenly. Remove from heat and then add in the powder sugar, vanilla extract and the milk, continue stirring until the frosting is smooth and spreadable. Spread on cake immediately. Slice, serve and enjoy!