40cm loaf tin - if you want to make a smaller cake, simply halve the ingredients - the cooking time will remain the same
Start by zesting and juicing all the lemons.
Sift the flour four times and set aside.
Cream the butter and caster sugar together until pale and soft. Add the eggs one at a time, along with half of the zest. Add half of the lemon juice, again very slowly, to the mix. Add the flour and mix until the batter falls gently from the whisk. If it's too thin, add 50g of flour, if it's too firm, continue whisking.
To make the drizzle, add three quarters of the lemon juice to the demerara sugar and whisk together.
Line your baking tin and bake the cake for 1 hour at 160C. At this point the cake should be firm.
Take a pastry brush and quickly paste the remaining lemon juice on top of the cake.
Place back in the oven and cook for a further 15 minutes.
Take the cake out of the oven, ensure it is well risen and springs back when touched. Take a skewer and make 20 or so holes through the top of the cake.
Place your drizzle mixture in a jug and pour it into the holes. Paste the rest of the mixture on top of the cake using the back of a spoon to flatten it out, leave to cool.
Take the zest and sprinkle caster sugar over it, mix it up with your fingers and lay it out flat to dry for 2 hours.