First, you’ll need 1/2 cup of soft (room temperature) shortening. That’s about 100 grams, if it’s vegetable shortening – if butter, it will weigh about 110 grams, since it has some more water in it. Add 3/4 cup granulated sugar (150g) to it and “cream” them together, either with an electric mixture or by hand if you’re feeling vigorous. Mix in one large egg, and then mix in 4 teaspoons (20 mL) of lemon or lime juice. At this point, it would be a good idea to start warming up the oven to 350F (about 177C).
In a separate bowl, mix together 2 cups of flour (250g), 1 teaspoon baking soda (5g), and 1/2 teaspoon salt (2.9g). Figure out first if you want any additions (see next paragraph), because once you mix everything together, you will of course be bringing the lemon juice and baking soda together, and the resulting carbon dioxide will not sit around forever. So add the dry mixture in portions to the shortening/sugar/egg mixture with very light stirring, and then add 1 cup of the mashed ripe bananas (about 300g) and mix that in lightly as well.
At this point, if you desire, there are many possible additions. 1/2 cup of chopped nuts (100 to 120g) will always work well (we’ve used walnuts or pecans). I’ve seen golden raisins in there, or chopped cranberries or cherries, or chocolate chips as well – it all depends on which direction you want to go! Or you can stick with the plain austerity that comes with a bowl full of butter, sugar, and ripe bananas. No matter what you add, remember the light stirring part – the key thing about all “quick bread” recipes (and muffins, etc.) is that you don’t want to work the flour mixture very much to avoid the formation of stretchy gluten. I have been given banana bread that was run through an automatic bread machine (with kneading, etc.), and it was. . .unusual.
Scrape the batter into a bread loaf pan and cook it for at least an hour – depending on your additions, you may need more. The “stick a straw/wooden toothpick/skewer into it” is probably the best test – this probe should come out cleanly, not with stuff still clinging to it. Once done, turn the bread out to cool.