In a large bowl, cream the shortening and sugar until light and fluffy.
Add the eggs, one at a time, beating well after each addition.
Beat in vanilla. Add bananas and mix well.
Combine the flour, baking powder, baking soda and salt; add to the creamed mixture alternately with sour cream, stirring just until combined. Stir in walnuts.
Pour into a greased and floured 10-in. fluted tube pan.
Bake at 350° for 50-55 minutes or until a toothpick inserted near the center comes out clean.
Cool for 10 minutes before removing from pan to a wire rack to cool completely.
Place a piece of waxed paper under the wire rack before adding the glaze.