Preheat oven to 350*.Coat 2 (8-inch) round cake pans with cooking spray.
In a large bowl with an electric mixer, cream the granulated sugar and shortening until light and fluffy. Add eggs and beat thoroughly. Gradually blend in baking soda ,flour, and salt. Beat in mashed banana and 1 teaspoon vanilla until thoroughly combined.Pour mixture into prepared cake pans.
Bake 25 to 30 minutes, or until a wooden toothpick comes out clean.Let sit 5 minutes, then remov cakes from pans and place on a wire rack to cool.
In another bowl, combine cream cheese,peanut butter, and butter; beat until fluffy.Add confectioners sugar and 1 teaspoon vanilla. Beat until thoroughly combined. Frost cake,then sprinkle with peanuts...