Preheat oven to 350 degrees. In a large mixing bowl or the bowl of a stand mixer fitted with a paddle attachment cream together shortening, sugar and eggs. Add mashed bananas and blend on low until incorporated. Over blending or beating will result in tough bread, so keep it slow.
In a separate bowl sift together flour, baking powder, baking soda and cinnamon. Gradually add to wet mixture until combined.
By hand, fold in walnuts with a spatula. Lightly coat a 9-inch bread pan with cooking spray and line bottom with parchment paper for easy removal. Transfer batter into bread pan.
Bake for 45-50 minutes or until top is lightly brown and it passes the toothpick test. If the top starts to brown too fast loosely cover with a leaf of aluminum foil.
Allow to cool slightly before eating. Store wrapped in aluminum foil at room temperature or freeze. Enjoy!
If you've tried this recipe, come back and let us know how it was!