Hummingbird Cake

In a large bowl, beat the bananas, oil, eggs, pineapple and vanilla until well blended. In another bowl, combine the flour, sugar, salt, baking soda and cinnamon; gradually beat into banana mixture until blended. Stir in walnuts. , Pour into 3 greased and floured 9-in. round baking pans. Bake at 350° until a toothpick inserted in the center comes out clean, 25-30 minutes. Cool for 10 minutes before removing from pans to wire racks to cool completely. , For frosting, in a large bowl, beat the shortening, butter, lemon zest and salt until fluffy. Add confectioners' sugar alternately with pineapple juice. Beat in cream. Spread between layers and over top and sides of cake. If desired, sprinkle with walnuts.