Preheat oven to 180°C.
Line a large loaf tin (approx 28x13x7cm) with baking paper. Set aside.
In a deep bowl mix the oil, sugar, banana, eggs and chocolate.
Sift in the flour and the baking powder. Mix to combine.
Cook for 50-60 minutes or until the top of the loaf is golden and an inserted skewers comes out clean.
Allow to cool in the tin until it feels firm enough to remove from the tin easily. Remove loaf from the tin and allow to cool completely on a wire rack.