These light sponge cakes, made with polenta and yogurt and filled with juicy blackberries, are the ultimate summertime treat – perfect for afternoon tea or a picnic!
Preheat the oven to 180C/160 fan/Gas 4. Add the butter, sugar and orange zest to the bow of a food mixer and using the beaters, beat until creamy.
Add the eggs a little at a time, along with a little of the flour to stop it from curdling and then stir in the remaining flour, polenta and yoghurt, followed by the blackberries.
Spoon the mixture into the tins and press a few remaining blackberries into the top of the cake mixture. Place the tins into the oven and bake for about 35 mins or until golden and risen. If browning too quickly, loosely cover with foil. Leave to cool for at least 10 mins then loosen with a knife and turn out onto a wire rack to cool completely. Dust with icing sugar to serve.