1 2/3 c. granulated sugar
1 c. vegetable oil
1 (15 oz.) can pumpkin
2 c. all-purpose flour
2 tsp. baking powder
2 tsp. ground cinnamon
2 tsp. pumpkin pie spice
1 tsp. baking soda
1 (8 oz) package cream cheese, softened
1/2 c. unsalted butter, softened
2 c. powdered sugar
1 tsp. vanilla extract
Preheat the oven to 350 degrees.
Using an electric mixer at medium speed, combine the eggs, sugar, oil and pumpkin until light and fluffy. Stir together the flour, baking powder, cinnamon, pumpkin pie spice, salt and baking soda. Add the dry ingredients to the pumpkin mixture and mix at low speed until thoroughly combined and the batter is smooth.
For a thick cake-like bar: Spread the batter into a greased 13 by 9-inch baking dish. Bake for 35-40 minutes. Test the center with a toothpick to check for doneness. For a thinner bar: Spread batter into a greased jelly roll pan and bake for 18-20 minutes, checking for doneness with a toothpick.
Let cool completely before frosting.
To make the frosting: Combine the cream cheese and butter in a medium bowl with an electric mixer until smooth. Add the sugar and mix at low speed until combined. Stir in the vanilla and mix again. You may need to add a little milk to make it spreadable if your butter wasn't soft enough. Spread on cooled pumpkin bars and cut into squares or cut bars first and frost individually.