Before You Start
1. Preheat the oven to 175°C on Bake Mode with a rack set on position 3.
2. Prepare three small loaf pans (140x76 mm) with pan spray.
3. Cream together the shortening, margarine, and sugar by hand, or in the bowl of a stand mixer on medium speed for two minutes.
4. Add in the egg, egg whites, mashed banana, milk, vanilla, and cinnamon.
5. In a separate bowl whisk together flour, kosher salt, baking powder, and baking soda.
6. Combine the wet ingredients into the dry.
7. Mix together just until combined.
8. Fold in the walnuts.
9. Divide batter evenly between the three loaf pans.
10. Bake until center of the bread is firm to the touch and a toothpick comes out clean — about 40–45 minutes.
11. After baking, allow to cool for 10 minutes, then remove the loaves from the pans and cool completely on a wire rack.