Pre-heat the oven to 180°C/160°C Fan/Gas mark 3. Grease a 23cm/ 9-inch spring form round cake tin and line with grease proof paper.

Put the butter, sugar and lemon zest into a mixing bowl and beat with an electric whisk until pale and fluffy. Gradually whisk in the eggs, then add the ground almonds, polenta, lemon juice and Baking Powder and carefully fold in until mixed thoroughly.

Spoon the mixture into the prepared tin and smooth to evenly cover the tin. Bake in the oven for about 1 hour or until a skewer inserted into the centre of the cake and it comes out clean. The cake should be golden brown and springy to touch. If the top starts to get too brown before it is cooked through then cover with foil.

While the cake is cooking make the drizzle by mixing together the lemon juice and sugar to make a syrup. 

Once the cake is baked pour the lemon drizzle over the cake straight after it comes out of the oven and leave to cool in the tin. Once cool remove from the tin and remove the greaseproof paper and sprinkle over the lemon zest. Your cake is now ready to serve and enjoy!