Sift together flour,baking soda,baking powder & salt. Set aside. Work butter until soft. Then work in sugar, a little at a time until smooth. Beat in eggs one at a time, add the vanilla,lemon rind and bananas. Stir in flour mixture alternating with sour cream. Last of all mix in nuts. Pour into a greased pan. Bake for 1 hour until toothpick comes out dry. Remove from pan and cool. Cut into thin slices--Enjoy!