Preheat oven to 190 degree c. Line muffin tray with cupcake cases.
Mash banana in a bowl.
Add in honey, oil and vanilla. Add in egg and milk and mix well.
Mix flour with baking soda, walnuts and mix well.
Add flour and fold gently.
Spoon it into muffin moulds and bake for 20 to 25 mins.
Remove and serve warm.