Try Delia's delicious lemon cake recipe filled with homemade lemon curd.
Equipment and preparation: You will need to grease two 18cm/7in sandwich tins 4cm/1½in deep, lined with baking parchment, also greased.
Preheat the oven to 170C/325F/Gas 3.
Measure all the cake ingredients into a mixing bowl and beat - ideally with an electric hand whisk - until you have a smooth, creamy consistency. Then divide the mixture evenly between the two tins and bake them on the centre shelf of the oven for about 35 minutes or until the centres feel springy when lightly touched with a little finger.
While the cakes are cooking, make the lemon curd, place the sugar and grated lemon zest in a bowl, whisk the lemon juice together with the eggs, then pour this over the sugar. Then add the butter cut into little pieces, and place the bowl over a pan of barely simmering water. Stir frequently till thickened - about 20 minutes. You don't have to stay with it - just come back from time to time to give it a stir.
When the cakes are cooked, remove them from the oven and after about 30 seconds turn them out on to a wire rack. When they are absolutely cold - and not before - carefully cut each one horizontally into two using a sharp serrated knife. Now spread the curd thickly to sandwich the sponges together.
For the icing, begin by removing the zest from the lemon - it's best to use a zester to get long, curly strips. Then sift the icing sugar into a bowl and gradually stir in the lemon juice until you have a soft, runny consistency.
Allow the icing to stand for 5 minutes before spreading it on top of the cake with a knife, almost to the edges, and don't worry if it runs a little down the sides of the cake. Then scatter the lemon zest over the top and leave it for half an hour for the icing to firm up before serving.