01 - Preheat oven to 350°F. Grease and flour a 9x5-inch loaf pan or line with parchment paper.
02 - In a large bowl, whisk together mashed bananas, eggs, oil (or butter), yogurt (or sour cream), sugar, and vanilla extract until thoroughly combined.
03 - In a separate bowl, sift together flour, baking soda, salt, and cinnamon until evenly distributed.
04 - Gently fold dry ingredients into the wet mixture, mixing just until incorporated. Do not overmix.
05 - Stir in nuts and/or chocolate chips if desired.
06 - Pour batter into the prepared loaf pan and smooth the top evenly.
07 - Bake for 50 to 60 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
08 - Remove from oven and let cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.