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. Pour into a greased and floured 10-in. fluted tube pan or 13x9 inch baking pan. Bake at 350° for 35 - 40 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.

In a medium bowl, add powdered sugar.

Place butter in a small saucepan. Melt butter over medium heat until bubbly. Cook, stirring occasionally until golden brown.

Remove from heat and pour butter into the bowl of powdered sugar. Add milk and vanilla, stir until smooth.