Preheat oven to 200ºC. Swirl oil in a 20 x 20 x 5 cm baking pan. Preheat pan in oven for 5 minutes.
Combine the polenta, flour, baking powder, bicarbonate of soda, sugar and salt in a large bowl. Stir in the buttermilk, egg and carrot. Carefully pour in oil from baking pan. Mix well. Pour batter into hot pan.
Bake until a toothpick inserted in the centre comes out clean, about 25 minutes. Let cool in pan 10 minutes. Turn out onto a wire rack and cool slightly before cutting. Serve warm.
Did you know
…that buttermilk is produced by adding live cultures to low-fat milk? This thickens the milk and gives it a pleasant creamy, tangy flavour. Buttermilk is a useful ingredient in baking, particularly in scones and muffins.