In fact, although my mother copied this recipe down for me from memory when I left home, I believe it originally came from the American Women's Cook Book that once belonged to my grandmother. Most annoyingly, it was recently featured on AbeBooks as being one of the bestselling out of print cookbooks. Annoying, I say, because my mother donated it to the Roxbury Latin Yard Sale several years ago.
1/2 cup (one stick) margarine
1 cup granulated sugar
1 cup mashed banana* (about 3; it helps if they are mushy)
1 teaspoon lemon juice
2 cups flour
3 teaspoons baking powder
Cream shortening and sugar together in medium size bowl. Add eggs, mix well. Add lemon juice to bananas and stir gently into batter. Add baking powder to flour and sift into bowl. Mix thoroughly until flour is completely absorbed.
Bake in loaf pan (I think mine is 8.5 x 4.5) at 350 for about an hour until top is firm and slightly brown. Stick knife in - if still gooey in center, cook for 5 more minutes.
Serve warm and with butter! Or cold - it cuts better once it's cooled.
* My brother always had a Johnny Malone-like ability to eat all the bananas just as my mother was about to make banana bread.