Preheat the Oven:Preheat your oven to 400°F (200°C).
Mix Wet Ingredients:In a large bowl, mash the bananas until smooth. Add milk, vegetable oil, granulated sugar, lemon juice, and vanilla extract. Mix until well combined.
Combine Dry Ingredients:In another bowl, whisk together the flour, baking powder, and salt.
Combine Wet and Dry:Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix.
Prepare for Baking:Spoon the batter into a muffin tin lined with paper liners or greased. Sprinkle a little brown sugar on top of each muffin.
Bake:Place the muffins in the preheated oven. Immediately reduce the temperature to 350°F (175°C). Bake for about 40 minutes, or until a toothpick inserted into the center comes out clean.
Cool and Enjoy:Let the muffins cool in the tin for a few minutes before transferring them to a wire rack to cool completely.