Preheat the oven to 180C/350F.
Peel the bananas and mash them up in a mixing bowl, using a fork.
Add the oil and sugar to the bananas and stir together. It looks unpleasant at this stage but I promise it will come together.
Add the flour, baking powder, and bicarb and mix everything together. It should be a bit lumpy looking - don't keep mixing hoping for a smooth batter, lumpy works here. You can add any fruit or chocolate chips at this stage.
Pour the batter into a loaf tin and pop it in the oven for 35 minutes. You can check it's ready by gently pressing the top of the loaf. If it leave an indent then it needs a bit longer (another five mins should do it), if it springs back then it's done.
Leave to cool in the tin. Slice and scoff!