Preheat oven to 350°F. Peel, slice, and mash bananas.
In a large bowl beat butter and sugar until fluffy. Add eggs, sour cream, and vanilla; blend well. Gradually add flour. Stir in bananas. Add baking soda and salt; mix well.
Spray a 9- × 13-inch baking pan with cooking spray. Pour batter into pan. Bake 20 to 25 minutes or until a toothpick inserted into center of cake comes out clean. Let cool.
To make frosting:
In a large bowl beat cream cheese, butter, and vanilla until fluffy. Gradually add powdered sugar. Mix until combined. Frost cake. Store in refrigerator until ready to serve. Makes 12 servings. Recipe from Culinary.net.