Pre-heat the oven to 180ºC/350°F and grease and line a standard size loaf tin (approximatley 20cmx12cm / 9" x 5") with baking paper.
In the bowl of a mixer, beat the butter and sugar together until light and creamy. Add the eggs one at a time, mixing well after each addition. Scrape down the bowl with a rubber spatula.
Beat in the bananas. At this point, your batter will split and look curdled. Don't be alarmed, the flour will fix that.
Add the dry ingredients then mix until just combined.
Transfer the batter to the prepared loaf tin and place in the oven.
Bake for 45 minutes or until a skewer inserted comes out clean. Cover with foil halfway to prevent over browning.
Remove from the oven and allow to cool before removing the banana bread from the tin.