Set the oven to 375°F (190°C) and prepare your muffin tin by greasing it with butter or a non-stick spray. Alternatively, you can line it with muffin liners for easier cleanup.
In a medium bowl, mash the overripe bananas until they’re soft and mushy, they’re key for making your muffins extra moist and sweet!
Once mashed, add the melted butter (let it cool slightly) and the beaten egg. Combine all ingredients until smooth, then add the vanilla extract and fold it into the mixture.
Now, add the granulated sugar for sweetness, followed by the lemon juice and zest. The zest gives a bright, fresh burst of flavor!
Then, stir in the baking soda, baking powder, and salt until everything is evenly mixed, but don’t overdo it, we just want everything to blend together.
Next, gently fold in the flour. Combine the ingredients gently, ensuring you don’t overmix, which will keep the muffins nice and fluffy.
To prevent the blueberries from sinking, toss them in a small ziplock bag with 2 tablespoons of flour.
Shake the bag to coat the blueberries evenly, then carefully fold them into the batter, avoiding overmixing (we’re aiming for those beautiful pops of color, not purple batter).
Pour the batter into each muffin cup, filling them to approximately two-thirds. If you’d like a little extra sweetness, sprinkle some coarse sugar on top before baking.
Put the muffin tin in the oven and bake for around 20 minutes, checking with a toothpick to ensure it comes out clean. Your kitchen will smell incredible, thanks to the mix of banana and blueberries!
Once baked, let the muffins sit in the pan for 2–3 minutes, then carefully place them on a wire rack to cool fully. Enjoy warm or store for later!