In a stand mixer or in a mixing bowl with electric hand mixer, blend the pumpkin, eggs, vanilla and oil.
Add the sugar, flour, salt, baking soda and cinnamon.
Prep a large baking sheet, jelly roll sized. I use a 13"x17". If yours is smaller then you may need to bake a little longer until the center is fully baked. Lightly spray or rub with oil. Pour batter on the sheet and spread out evenly.
Bake at 350° for 25 minutes.
Let cool completely before frosting! I make the frosting as it is cooling.
Cream Cheese Frosting
In a medium sized mixing bowl cream the butter and cream cheese. Add in the powdered sugar and vanilla extract. Mix well, best done with an electric mixer, till smooth.
When the bars are completely cooled CAREFULLY spread onto the bars. The top layer is easily peeled off if you rub the frosting on too hard. Cut into squares and serve.
Store covered tightly at room temperature for 4 days, or up to a week in the refrigerator.