Make sure the oven rack is in the center position and preheat the oven to 350 degrees F.
Lightly grease a 6 by 9-inch loaf pan with the vegetable shortening or butter.
Peel the bananas and place in a small mixing bowl. Mash with the back of a fork until there are no big lumps remaining.
In a large mixing bowl, combine the eggs, sugar, oil, and sour cream, and whisk until smooth.
Add the cinnamon, baking soda, baking powder, vanilla extract, salt, mashed bananas, and walnuts to the egg mixture and whisk to combine.
Add the flour and stir until just combined. Do not overmix!
Pour the batter into the loaf pan and bake until golden brown and risen, about 1 hour and 10 minutes.
Using oven mitts or pot holders, remove the loaf from the oven and let rest for 10 minutes in the pan. Turn out onto a wire rack to finish cooling before serving.
Yield: 1 loaf, serving 8
Donít be alarmed when your banana bread splits open on top while itís baking; this is supposed to happen. To be sure your bread is done, perform the toothpick trick.