Preheat your oven to 375°F (190°C). This ensures that your muffins bake evenly.
Grease your muffin tin with a bit of oil or line it with paper liners for easy removal.
In a large mixing bowl, combine the mashed bananas, granulated sugar, and vegetable oil. Mix until well blended. Then, add the egg, milk, and vanilla extract. Whisk until everything is smooth and creamy.
In another bowl, whisk together the flour, baking soda, baking powder, and salt. This helps to evenly distribute the leavening agents.
Gradually add the dry mixture to the wet ingredients, stirring gently. Be careful not to overmix; a few lumps are fine!
Gently fold in the blueberries, taking care not to crush them.
Scoop the batter into the prepared muffin tin, filling each cup about 2/3 full.
Place the muffin tin in the preheated oven and bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, remove the muffins from the oven and let them cool in the tin for about 5 minutes before transferring them to a wire rack to cool completely. Enjoy your delicious Banana Blueberry Muffins warm or at room temperature!
