Preheat the oven to 350 degrees F. Line three 9 x 5-inch bread loaf pans with paper liners and set aside. (this makes cleanup very easy)
In a large mixing bowl, cream together the shortening, vanilla and sugars. Add the eggs one at a time, beating well to incorporate. Add the bananas and sour cream to the mixture and thoroughly combine. Add the flour, salt, baking powder and baking soda, stirring to combine. Add nuts and stir to combine. Divide the batter evenly into bread pans. Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean. Be very cautious not to move the pans abruptly while baking, as this will make the bread fall. Allow to cool on a baking rack.