In large bowl, cream the shorting 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, stiring 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 tiithpick inserted near the center comes out clean.
Cool for 10 minutes before removing from pan to a wire rack to cool completely. Dust with confectioners sugar.