Place oven rack to lower 3rd position, preheat to 350F. Grease a 9x5 inch loaf pan so it won’t stick.
Cut bananas into pieces. Use medium speed on a mixer. ( we used 5 bananas for 2 cups of mashed bananas)
Mix flour, baking soda, salt, cinnamon in a bowl, set aside - these are dry ingredients
Using a mixer, in another large bowl, beat butter and brown sugar together on high speed until smooth and creamy, about 2 min.
On medium speed, add in eggs one at a time. Beat in yogurt, mashed bananas, vanilla extract.
On low speed, slowly beat dry ingredients in until no flour pockets remain. Add in nuts (optional).
Put it into the bread pan and bake for 65 minutes. After 30min, cover the bread with aluminum foil. After it’s done, insert a toothpick into bread and if it comes out clean, it’s done. (We baked another 20 minutes after the 65 minutes)
Remove from oven and let cool completely. Cover and store at room temperature for 2 days, or in fridge for up to a week. Taste best on day 2.