Preheat your oven to 350°F (175°C) and grease a 9x5-inch loaf pan.

Mash 3-4 very ripe bananas in a medium bowl until mostly smooth, leaving a few small lumps.

In a large mixing bowl, combine 1/3 cup melted butter with 3/4 cup brown sugar, then mix in 1 large egg and 1 teaspoon vanilla extract.

Whisk together 1 1/2 cups all-purpose flour, 1 teaspoon baking soda, and a pinch of fine salt in a separate bowl, then fold in the add-ins if using.

Combine the dry mixture with the wet ingredients, stirring gently until just combined.

Pour the batter into the prepared loaf pan and bake for 55-65 minutes until golden brown and a toothpick comes out clean.

Let the banana bread cool in the pan for about 10 minutes, then transfer it to a wire rack to cool completely.