Preheat the oven to 350. Makes 1 full-sized loaf or 2 small loaves
In one bowl, combine first 4 ingredients. Use a potato masher, fork, or spoon to squish the banana and mix the ingredients together. It is alright for there to be small (1 centimeter) chunks of banana in the batter, but you want most of the banana to be reduced to mush.
In another bowl, combine the Dry ingredients. Add cinnamon here if desired.
Combine the wet and dry ingredients and mix until the ingredients are blended together.
If you like, stir in any of the optional ingredients here. If using more than one ingredient, the total should be about 1/2 cup.
Pour the dough into greased baking pans and bake until a toothpick inserted in the center comes out clean. Small loaves take around 30 minutes, a normal-sized loaf takes around 50 minutes.
Remove from the oven. This bread is great warm, but it is excellent cold too.
After they have cooled for 5 or 10 minutes the loaves can be removed from the pan to cool. Once they are cool they can be individually wrapped and frozen.