Begin by making the pastry as described in shortcrust pastry recipe below, or you can watch how to make it in our Cookery School video, sifting in the icing sugar into the rubbed in mixture then adding the yolk with the water before making the dough. Then leave it to rest in a polythene bag in the refrigerator for 30 minutes. Meanwhile, make the filling, grate the zest from the lemons, and squeeze enough juice to give 225 ml. Now break the eggs into a jug, and add the sugar to the eggs and whisk to combine, but don't overdo it or the eggs will thicken. Next add the lemon juice and zest followed by the cream, and whisk lightly. Roll the rested pastry as described in the basic pastry recipe below to 30cm in diameter then carefully roll the pastry round the rolling pin and transfer it to the centre of the tin. Now, using your hands, gently press the pastry into the tin to line the base and sides making sure you ease the pastry into the corners and press it against the sides then trim off any excess pastry around the top edge with a sharp knife. After that use your fingers again to press the sides all round to the pastry so it is slightly proud of the tin. All you now need to do is prick the base all over with a fork, as this will release any trapped air, which is what causes the centre to rise up. Then pop it in the freezer to chill for 30 minutes. To cook the pastry base, pre-heat the oven to 190°C, gas mark 6 and place the baking sheet near the centre to preheat as well.