Start by greasing a 9-inch bread pan with butter or non-stick spray and preheat your oven to 350°F (175°C).

In a large mixing bowl, whisk together ½ cup of melted unsalted butter, ½ cup of brown sugar, and ½ cup of granulated sugar until smooth. Add ½ cup of sour cream, 2 large eggs, and 1 teaspoon of vanilla extract until well combined.

Peel and mash 3 large ripe bananas until smooth, then fold them into the wet mixture.

In a separate bowl, whisk together 1.5 cups of all-purpose flour, 1 teaspoon of baking soda, ½ teaspoon of baking powder, ½ teaspoon of salt, and 1 teaspoon of ground cinnamon. Gradually add this to the banana mixture and fold gently until combined.

Pour the batter into the prepared loaf pan and smooth the top. Bake for 45–55 minutes until a toothpick comes out clean.

Let the bread cool in the pan for 10-15 minutes, then transfer to a wire rack to cool completely.