Preheat oven to 350 degrees. Spray a loaf pan with non-stick cooking spray or grease with butter and set aside.
Add the stick of butter to a large bowl and microwave for 1 minute, or until melted.
Add the bananas to the same bowl and mash with a fork.
Add the vanilla extract and egg to the bowl and use the same fork to mash and stir until no yellow streaks of egg remain.
In a second large bowl whisk together the flour, sugar, baking soda, salt, and cinnamon.
Add the dry ingredients to the wet ingredients and mix together with a spatula just until combined.
Pour the batter into prepared loaf pan and bake for 45-55 minutes until a toothpick inserted in the center of the bread comes out clean.
Notes
STORING: To keep the bread moist, allow it to cool completely, wrap it in a layer of plastic wrap, and then store it in a freezer size zip-top bag, or a large plastic container with a tight-fitting lid. It will last on the counter for up to 3 days, or in the refrigerator for up to 6 days. Alternately, you can wrap and freeze for up to 2 months.LOAF PAN: For this recipe you will need a standard size (approx. 9"x5") inch loaf pan. Alternately, you can use a standard-sized muffin tin and bake the muffins for 25-30 minutes.ADDITIONS: You can add 1 cup of chopped nuts or chocolate chips to the batter before baking, if desired.