Preheat the oven to 350°F (175°C).

In a mixing bowl, mash the bananas with a fork.

Add melted butter to the mashed bananas and mix well.

Stir in the sugar, beaten eggs, and vanilla extract.

Combine the flour, baking powder, baking soda, and salt in a separate bowl.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Gently fold in the blueberries.

Pour the batter into a greased loaf pan.

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

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