Sieve all purpose flour, baking soda, salt into a bowl so that there are no lumps
Smash banana in another bowl, add egg, sugar, molten butter, beat well until are mixed well
Add flour little by little and mix well into batter
Arrange paper linings in the muffin plates
Scoop the muffin mix into each cups
Pre-heat oven to 180°C
Bake the muffins for 25~30min