1

Preheat oven to 160°C. Lightly spray a 14cm x 24cm (top measurement) loaf tin with oil. Line base and sides with baking paper. Sift cocoa into a heatproof bowl, add ¼ cup (60ml) boiling water and stir to a smooth paste. Set aside to cool.

2

Whisk banana, eggs and vanilla in a medium bowl until combined. Sift flour into a separate large bowl and rub in the oil spread with your fingertips. Stir in sugar, then add banana mixture and stir until well combined. Stir a third of the mixture through the cocoa paste until well combined.

3

Spoon dollops of cocoa mixture and the remaining banana mixture alternately into the prepared tin, then swirl with a flat-blade knife for a marbled effect.

4

Bake for 50 minutes-1 hour, until a skewer inserted into the centre of loaf comes out clean. Stand loaf in the tin for 10 minutes, then turn out onto a wire rack to cool. Cut into 12 slices.