Heat oven to 180°C. Grease and line a medium loaf tin.
In a large mixing bowl, mash the bananas with a fork.
Add the oil and sugar, then the flour, baking powder and cinnamon. Combine well.
Fold in the ground walnut and add the milk.
Finally , fold in the chopped walnuts and chocolate chips, then transfer the batter into the prepared tin, spreading it out evenly.
Bake in the middle of the oven for 40-45 minutes. After 20 minutes of baking, cover the tin with foil ( if the top is already is brown). After 40 minutes test the cake with an inserted skewer - if it comes out clean, it’s done, if it’s wet, bake it for another 5-1 0 minutes.
When the cake is cooked through, take the tin out of the oven. Leave the cake in the tin for 5 minutes, then move it to a wire rack. Let it cool completely before slicing it.