Heat the oven to 180C/160C fan/gas 4 and line a 900g loaf tin with baking parchment (our tin was 19 x 9 x 6cm).

Put all the ingredients, except the sliced banana, 1 tbsp caster sugar and the icing sugar, in a large bowl and stir until smooth and combined.

Pour the mixture into the tin and put the two remaining banana halves cut-side up across the top of the batter, pressing down slightly.

Sprinkle over the caster sugar. Bake for 1 hr-1 hr 15 mins until a skewer comes out clean, covering with foil towards the end of cooking if it browns too much. Dust with icing sugar and leave to cool.