Kay Williams’ Frosted Banana Bars

1 cup butter, softened
3 cups white sugar
4 eggs
2 cups sour cream
2 teaspoons vanilla
4 cups all-purpose flour
2 teaspoons baking soda
½ teaspoon salt
2 cups ripe bananas, mashed
1 cup pecans or walnuts, chopped (optional)
2 (16-oz) containers cream cheese frosting
In a large mixing bowl, cream together butter and sugar. When smooth, add eggs, one at a time while beating. Then stir in sour cream and vanilla. Combine and stir in flour, baking soda, and salt. Finally, add in mashed bananas and nuts. Spread evenly in large jelly roll or cookie pan that has been sprayed with Pam. Bake for 45-50 minutes at 350 degrees, or until toothpic inserted into the center comes out clean. Allow bars to cool completely before frosting with cream cheese frosting.