Ingredients for 6 people:200 g plain flour (plus 2 spoonfuls for the cake tin)70 g potato starch200 g cane sugar120 g butter (plus a knob to grease the cake tin)3 eggs at room temperature125 g plain, low fat Greek yoghurt16 g baking powder1 untreated lemon250 g blueberries icing sugar
Melt the butter in a small, heavy-bottomed saucepan over a low heat, then let it cool down. In a bowl, beat the eggs and the sugar with a whisk – preferably an electric one – until light and fluffy. Add the grated zest of the lemon, the melted butter – making sure it’s cold – and the yoghurt, and stir gently with a wooden spoon. Sift the flour with the potato starch and baking powder and, still using the wooden spoon, fold them into the mixture a little at a time. When smooth and even, pour the batter into a 24 cm cake tin (carefully greased with butter and dusted with flour), level the surface and scatter the blueberries on top. Bake in a preheated oven, at 180 °C, for 35-40 minutes (use the toothpick test to see if it’s cooked: stick one into the centre of the cake, if it comes out clean, it’s ready, otherwise continue baking for a few minutes). When the cake is cooked, take it out of the oven and leave to cool before turning it out of the tin. Then dust it with icing sugar and serve.