Preheat your oven to 350°F (175°C). Line a loaf pan with parchment paper or grease it with non-stick spray.
In a large mixing bowl, mash the ripe bananas using a fork until smooth.
Add the melted butter, eggs, vanilla extract, and Greek yogurt (or sour cream) to the mashed bananas. Whisk until well combined.
In a separate bowl, combine the flour, granulated sugar, brown sugar, baking soda, salt, and cinnamon (if using).
Add the dry ingredients to the banana mixture. Stir gently until just combined. Avoid overmixing to keep the bread light and fluffy.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Let the banana bread cool in the pan for 10-15 minutes before transferring it to a cooling rack to cool completely.
Slice the banana bread and enjoy it warm or at room temperature.
