Preparation time: 5'
Baking time: 30'
For the topping:
In a bowl add the bananas, oil, milk and eggs and mix.
Add flour, baking powder, baking soda and salt and mix.
Fold gently the walnut chunks.
Pour the butter into the muffin tins and sprinkle with the cinnamon topping combined by cinnamon, brown sugar and walnut chunks.
Bake in a preheated oven at 180C for 25'-30' or until a toothpick inserted comes out clean.