Preheat oven to 350°F/180°C. Grease an 8½ x 4¼-inch loaf pan.
Place bananas in a large bowl and mash them. Add all the other ingredients to the bowl, and whisk just until combined.
Pour batter into prepared loaf pan and bake for 50-60 minutes, or until a toothpick inserted into the center of the cake comes out clean. Let the cake cool for 15 minutes on a wire rack, then turn it out from the pan and let it cool completely.
Store cake at room temperature or in the fridge in an airtight container for up to 4-5 days. Serve at room temperature.