Blueberry and limoncello drizzle cake
For the sponge: Spray oil (vegetable or sunflower spray’s fine); 125g caster sugar; 100g unsalted butter; softened, 100g full-fat Greek yogurt, 2 eggs, lightly beaten; 250g self-raising flour; 4 egg whites; 2tsp baking powder; ½tsp vanilla extract; finely grated zest of 2 unwaxed lemons (if waxed, wash in hot, soapy water and dry them to get rid of the wax before using); 200g blueberries.
For the topping: 50g icing sugar, sifted; 2tbsp limoncello (or lemon juice for an alcohol-free version)
Preheat the oven to 170C (Fan 150C/gas mark 3) and set the shelf in the middle. Spray a 20cm round, loose-bottomed, deep cake tin with oil, line the bottom with baking parchment and set aside on a baking sheet.
Put the sugar, butter and yogurt into a food mixer or large bowl and beat with a whisk until well combined. Add the two whole eggs and half of the flour and beat for a good few minutes, until the mixture is well blended and starts to look a little smoother.
Whisk the four egg whites until light and frothy then fold them into the mixture with the rest of the flour, the baking powder, vanilla extract and lemon zest and beat until you have a smooth batter. Finally, stir half of the blueberries through. Pour the mixture into the tin and smooth down evenly with the back of a spoon. Arrange the remaining blueberries, flat side down, on the top in a few lines across the centre. Pop into the oven for about 25-30 minutes until a knife inserted into the centre comes out clean. Put the icing sugar into a small bowl. Stir in the limoncello (or lemon juice) to give a smooth, runny mixture and, once the cake’s cool, slowly spoon the topping all over, allowing it to pour over the edges.