Line muffin cups or tray with liners or simply grease them with oil or butter. Preheat oven @180° C for 10 minutes
Mash the banana with a fork.
In a mixing bowl add the mash banana, sugar, milk, vanilla essence and mix well until combine.
Seive in the flour, baking powder, baking soda and salt. Sift them.
Gently fold the wet and dry ingredients to make a smooth batter without lumps. Do not overmix the batter.
Add in the vinegar and mix.
Dust the nuts with flour to prevent from sinking at the bottom. Add in the nuts to the batter and give a quick mix. (Reserve some for topping)
Pour the batter into the prepared muffin cups or tray till ¾ of the cavity.
Tap the pan on the surface for couple of times to release any air bubbles inside. Now sprinkle the chopped nut on the top.
Bake at a preheated oven @180° C with both rods switched on for 20 to 25 minutes or until a toothpick or skewer inserted comes out clean.
Remove from the oven and let the it stand in the pan for about 5 minutes.
Transfer the muffins onto a cooling rack and let it cool down completely.
Serve it as a snack with two/coffee. It's perfect for kids tiffin box too.