PREPARE: Heat the oven to 180°C / 350°F / Gas 4 and line the base and grease the sides of a 26cm (10 in.) springform cake pan.

CREAM THE BUTTER AND SUGAR: In the bowl of a stand mixer or a large mixing bowl combine the sugar and the lemon zest, then use your fingers to rub the sugar and zest together releasing all the aromatic oils. Using an electric mixer, beat the eggs and lemon sugar together for 5 minutes until pale and fluffy. Add the butter, vanilla extract and 50ml of the lemon juice and beat until well combined.

FOLD THROUGH DRY INGREDIENTS: Whisk together all remaining dry ingredients including the chocolate (you can also pulse them together in a food processor), then fold the dry ingredients gently but thoroughly through the beaten egg mixture.

BAKE: Pour the cake batter into the prepared pan, give it a little shake to even the surface, then bake in the preheated oven for 35-40 minutes until golden brown and a skewer inserted into the centre of the cake comes out clean. Keep an eye on the cake in the last 10 minutes of cooking time and if it is starting to over brown cover loosely with a square of tinfoil.

COOL AND SERVE: When the cake is cooked, remove from the oven and allow to cool completely in the tin. When the cake is cool, run a small sharp knife around the edge of the cake, remove from the tin and transfer to a serving plate. Dust generously with powdered sugar and serve.