Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment paper for easy removal.

In a large mixing bowl, combine the mashed bananas and sugar. Mix well until smooth.

Add the softened butter to the banana mixture and blend until fully incorporated.

Beat in the eggs one at a time, followed by the vanilla extract.

In a separate bowl, whisk together the baking soda, salt, and flour. Gradually add this dry mixture to the wet ingredients, stirring until just combined. Be careful not to overmix.

Gently fold in the blueberries, ensuring they are evenly distributed throughout the batter.

Pour the batter into the prepared loaf pan and smooth the top with a spatula.

Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center comes out clean.

Allow the bread to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.