Preheat your oven to 180°C (160°C fan) / 350°F and lightly grease a 2lb loaf tin. Line it with baking paper for easy removal.
Cream the butter and sugar in a large mixing bowl until light and fluffy using a wooden spoon or hand mixer.
Beat in the eggs one at a time, mixing thoroughly after each addition.
Mash the bananas in a separate bowl until smooth, then fold them into the butter, sugar, and egg mixture.
Sift the flour, baking powder, and salt together, then gently fold into the wet mixture until combined. Do not overmix.
Add extras like chocolate chips or walnuts if you want to create a twist such as a banana chocolate chip loaf.
Pour the batter into the prepared loaf tin, smoothing the top with a spatula.
Bake for 50–55 minutes until golden brown and a skewer inserted into the centre comes out clean.
Cool the loaf in the tin for 10 minutes, then transfer to a wire rack. Slice once fully cooled.