Preheat oven to 350° F. Prepare 13 x 9 pan with vegetable pan spray.
In medium bowl, stir together flour, baking soda and salt; set aside. In large bowl, beat butter and granulated sugar until light and fluffy. Add eggs, vanilla and banana; mix well. Alternate adding flour mixture and sour cream to banana mixture, stirring until just combined.
Pour batter into pan, bake 40 to 45 minutes or until toothpick inserted in center of cakes comes out clean. Set pan on cooling grid; cool completely.