For the cake:
1 1/4 cups sugar
1 cup sour cream
2 eggs
4 T. butter, melted
3 - 4 ripe bananas, mashed
2 tsps. vanilla
2 cups flour
1/2 tsp. salt
1 tsp. baking soda
1 cup chopped walnuts (optional)
For the frosting:
4 T. butter, softened
1/2 cup heavy whipping cream
1 tsp. vanilla
2 1/2 cups powdered sugar
Preheat the oven to 375 degrees. Grease a 9x13 pan with nonstick cooking spray.
In a medium bowl, cream together sugar, sour cream, egg and melted butter. Add mashed bananas and vanilla. Add flour, salt and baking soda; mix well. Pour into greased pan and bake for 20 - 25 minutes. Cool completely before frosting.
To make the frosting - cream the butter and powdered sugar together. Slowly add the heavy cream; stir until smooth. Stir in vanilla extract. Spread on cooled cake.