Directions

1. Preheat the oven to 170C/150C Fan/Gas 3½. Line the base and sides of a 13x20cm/5x8in loaf tin with baking paper.
2. Mix together the butter and sugar in a bowl using an electric whisk or wooden spoon until light, airy and combined.
3. Crack the eggs into a small bowl and lightly whisk in the vanilla. Gradually pour into the butter and sugar, mixing as you go. Don’t worry if the mixture curdles, it will come back together.
4. Mix the flour, spices and baking powder together in a separate bowl. When combined, sift into the butter mixture, followed by the ground almonds, folding into the mixture with a metal spoon.
5. Mash three of the bananas in another bowl, then fold into the cake mixture. Pour into the prepared tin.
6. Slice the remaining banana down the middle vertically. Place across the top of the batter, cut-side up. Bake on the middle shelf of the oven for 60–75 minutes, until a skewer inserted into the middle comes out clean. If it starts to brown too quickly, cover loosely with foil.
7. Leave to cool slightly, then remove from the tin onto a wire rack to cool completely.