Pumpkin Sheet Cake and the coolest tip ever

So, I was watching Studio 5 a couple weeks ago and they had a girl on that used bean puree instead of oil in her brownies. She said you can use equal amounts of bean puree in place of vegetable oil in almost any recipe.It cut out a lot of calories and fat and adds fiber. I was very skeptical but thought I would give it a shot. I made this pumpkin sheet cake and let me tell you, I honestly couldn't tell the difference. I used great northern beans in place of the oil and they taste just the same. I am totally using this trick in most of my baking recipes that require oil. This girl said to use the same colored bean puree as what you are making. For instance, she made brownies and used black beans. Here is the segment on Studio 5. I am so excited about this!

Pumpkin Sheet Cake

1 (16 oz.) can pumpkin
2 c. sugar
1 c. vegetable oil (or 1 c. bean puree)
4 eggs, lightly beaten
2 c. all purpose flour (I used 1/2 whole wheat and 1/2 all purpose)
2 tsp. baking soda
1 tsp. ground cinnamon
1/2 tsp. salt

Frosting:
1 (3 oz.) pkg cream cheese, softened (I used fat free with good results)
5 Tbsp. butter or margarine, softened
1 tsp. vanilla
1 3/4 c. confectioners sugar
3-4 tsp. milk
Chopped nuts

In a mixing bowl, beat pumpkin, sugar and oil (or bean puree). Add eggs; mix well. Combine flour, baking soda, cinnamon, and salt; add to pumpkin mixture and bean until well blended. Pour into a greased 15x10 inch baking pan (I use my jelly roll pan which I think is 11x18). Bake at 350 for 25-30 minutes or until cake test done. Cool completely.

For frosting, beat the cream cheese, butter and vanilla in a mixing bowl until smooth. Gradually add sugar; mix well. Add milk until frosting reaches desired spreading consistency. Frost cooled cake and sprinkle with nuts. Yield 20-24 servings.