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.
NOTE ON SUBSTITUTIONS: I've had a couple of questions about substituting the vanilla extract in this recipe. As always the recipe is best as written! I don't recommend using almond extract, because the flavors just don't seem to pair well and the almond overtakes the banana. You CAN add banana extract if you'd like, but, keep in mind it will have more of an artificial banana flavor.NOTES ON STORING THIS BREAD: To keep your bread moist, allow it to cool completely then wrap in a layer of plastic wrap and then store 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. NOTE ON LOAF PAN: For this recipe you will use a standard size about 9x5 inch loaf pan for one loaf of bread. Alternately, you can use a standard sized muffin tin and bake for around 25-30 minutes.NOTE ON ADDITIONS: You can add 1 Cup of chopped nuts or chocolate chips to the batter before baking if desired.