Preheat your oven at 160°c/325°f, Gas No 3.
Prepare 2 20cm/8inch round cake tins with greaseproof paper.
Cream your butter with the sugar, lemon rind and a pinch of salt for 3 to 4 minutes, until appearance is light a fluffy.
One at a time, beat in the eggs, adding a tbsp of flour, lemon juice and milk with each. Sieve together the rest of the flour and the baking powder, then gently fold this into the egg mixture with a large metal spoon.
Split your prepared mixture in to the two cake tins and smooth the tops. Bake in the centre of the oven for 1 ½ to 1 ¾ hours.
Tip: Pop a wooden cocktail stick in the centre of your cakes to test if they are done (the cocktail sticks will come out clean if they are).
While the cakes are baking, it’s now time to make the lemon curd filling.
Start by melting butter over a pan of simmering water. Next, beat together the eggs and extra yolk, then combine with the sugar, lemon rind and juice.
Add the mixture to the melted butter and cook gently (not allowing to boil) until the curd thickens enough to cover the back of a spoon. Don’t allow to overheat as this could make the mixture curdle.
Pour into a storage container and allow to cool as your cakes bake.
Once you’re satisfied the cakes are baked, take out of the oven and leave them in the tin for 5 minutes. Then, turn the cakes out on to a wire cooling rack.
While they are warm, mix together the juice of ½ a lemon and a little icing sugar, and drizzle this over both cakes to keep them moist.
Allow to go cold, then peel off the greaseproof paper.
Spread a desired level of lemon curd on to the top of one of your cakes, then place the other cake on top, forming a sandwich.
Next, whip up some icing using icing sugar and lemon juice to taste.
Pour over the top of your cake, allowing to trail the outside. As a finishing touch, decorate with lemon rind.
If you try this recipe for yourself, be sure to share your photos with us over on our social media platforms. We'll be getting in The Great British Bake Off spirit over the next few months, so watch this space for more baking inspiration.