Creating Blueberry Cinnamon Swirl Banana Bread is easy when you follow these simple steps:

1. Preheat Oven: Start by preheating your oven to 350°F (175°C). Grease a 9×5-inch loaf pan.

2. Mix Wet Ingredients: In a large bowl, combine the melted butter with the mashed bananas. Mix in the sugar, beaten egg, and vanilla extract until well incorporated.

3. Add Dry Ingredients: Sprinkle the baking soda and salt over the banana mixture. Stir to combine.

4. Incorporate Flour: Gradually mix in the all-purpose flour until no flour streaks remain. Be careful not to over mix the batter.

5. Prepare Blueberries: Gently fold in the blueberries into the batter.

6. Create the Cinnamon Swirl: In a small bowl, mix the cinnamon and brown sugar together. Reserve about 1/4 of the banana batter and layer half of the remaining batter into the bottom of the prepared loaf pan. Sprinkle half of the cinnamon mixture on top, then add the remaining batter, and finish with the rest of the cinnamon mixture on top.

7. Swirl: Use a knife or a toothpick to gently swirl the cinnamon mixture into the batter.

8. Bake: Place the pan in the preheated oven and bake for 55-65 minutes, or until a toothpick inserted in the center comes out clean.

9. Cool: Once baked, remove the banana bread from the oven and allow it to cool in the pan for about 10-15 minutes before transferring it to a wire rack to cool completely.

This straightforward method will guide you to successfully create this incredible dessert.