Preheat your oven to 350°F (175°C).

Grease your loaf pan with butter or cooking spray.

In a large mixing bowl, mash the ripe bananas until smooth.

Add the melted butter to the mashed bananas and stir until well combined. Then, mix in the beaten egg and vanilla extract.

In another bowl, whisk together the flour, baking soda, and salt.

Gently fold the dry ingredients into the wet mixture until just combined.

Carefully fold in the blueberries.

Pour the batter into the prepared loaf pan and smooth the top.

Bake for 60 minutes or until a toothpick inserted into the center comes out clean.

Let the banana bread cool in the pan for 10 minutes before transferring it to a wire rack.