Via: Helen Cathcart
Preheat the oven to 170°C/gas mark 3. Grease and line a 23cm loose-bottomed cake tin with baking paper. Separate 5 of the eggs, placing the whites in one bowl and the yolks in another. Crack the remaining whole egg into the bowl with the yolks and add 300g of the sugar and the zest of the lemons.
Whisk the yolks and sugar until the sugar more or less dissolves into the yolks, then beat in the almonds. This will be an almost impossibly thick batter, but that is normal. Using a clean whisk, whisk the egg whites to fairly stiff peaks. Scoop one third of the egg white into the yolk mixture and beat vigorously to slacken.
Gently fold the remaining egg white into the batter using a spatula or large metal spoon, being careful not to deflate the whites. Pour the batter into the prepared cake tin and bake for 45-50 minutes, until a skewer inserted into the centre comes out fairly clean – there may be the odd moist crumb on there.
While the cake bakes, make the syrup. Put the remaining sugar into a saucepan with the juice of the lemons, 50ml water and the rosemary sprigs. Bring to a boil, stirring. Boil for 1 minute, then set aside until the cake is baked. As soon as the cake comes out of the oven, stab the cake repeatedly with a skewer, then pour the syrup over the top and leave it to soak while the cake cools completely in the tin.
Perfect Plates by John Whaite (Kyle Books, £18.99)