Adjust the oven rack to the lower third position and preheat the oven to 350°F (175°C). Lowering the oven rack prevents the top of your bread from browning too much. Grease a metal 9x5" (25x10cm) loaf pan with butter or oil.

Smash the bananas and put them aside. Mix the flour, baking soda, salt, and cinnamon together in a medium bowl.

Using a handheld or stand mixer, mix the butter and brown sugar together on high speed until smooth and creamy, about 2 minutes. With the mixer running on medium speed, add the eggs one at a time, mixing well after each addition. Then mix in the yogurt, mashed bananas, and vanilla extract until combined.

With the mixer running on low speed, slowly beat the dry ingredients into the wet ingredients until no flour pockets remain. Do not over-mix. Add in the nuts or chocolate if you want.

Pour and spread the batter into the greased baking pan. Bake in the oven for about 60 minutes. Loosely cover the bread with aluminum foil after 30 minutes to prevent the top from getting too brown. The bread is done when a toothpick inserted in the center comes out clean with only a few small moist crumbs. This can be after 60 minutes depending on your oven, so start checking it every 5 minutes after the bread has been in the oven for an hour.

Remove bread from the oven. Allow the bread to cool in the pan for 1 hour. Remove the bread from the pan and cool bread on the table until it is ready to be sliced and served.

You can store banana bread at room temperature for 2 days or in the refrigerator for up to one week. Remember to cover it so it wont get dry. Banana bread tastes best on the second day since the baking, after the flavors have settled together.