Ingredients
Method
Preheat oven to 180°C. Grease and line a 23cm x 33cm Swiss roll pan. In a bowl or food processor, beat the butter and sugars. Add the mashed banana, yoghurt, egg and vanilla and mix lightly. Stir in the grated courgette.
Bring the milk to the boil in a small pan or microwave, stir in the baking soda to dissolve. Add to courgette mixture. Sift in the flour, baking powder, salt and spices and mix to combine.
Spread in the prepared pan. Bake for 35-37 minutes, or until a skewer inserted in the center comes out clean. Remove and let cool completely.
Meanwhile, make the Caramel buttercream icing (see below), and spread on cake when cake has cooled.
Caramel buttercream icing
Beat butter and icing sugar at a low speed until combined, then increase speed and beat for 6-8 minutes until pale. Add caramel and beat, adding the milk gradually if needed.
If you want to amp up the caramel icing to the next level, warm another 2 tablespoons of caramel in the microwave, stir until smooth and splatter it over the icing. Add a pinch of flaky sea salt if you like a hint of salted caramel.
1 medium banana yields about ½ a cup when mashed. You can use a flavoured yoghurt or natural, or swap the yoghurt for buttermilk, or the same amount of milk soured with a drop of lemon juice.
Note