Preheat the oven to 180 degrees C
Grease two 20cm sandwich tins and line the bottom of each tin with baking paper.
Using an electric whisk cream the butter and sugar until it is a pale yellow colour, the lighter you can get it the better, this means there is more air in the mixture and will result in a lighter cake.
In a small bowl, beat the eggs using a fork, then fold in the eggs a little at a time to the creamed mixture using a metal spoon. Making sure the eggs are fully incorporated each time.
When all the eggs have been added sift in the flour then fold it in. Fold in the lemon zest. Then fold in the milk, until you have a thick dropping consistency.
Divide the mixture between the two tins and place in the middle of the oven, switching the two tins halfway through baking so they are both evenly browned.
After 20 mins use a metal skewer to check the cakes are cooked through, the skewer should come out clean.
Remove from the oven and leave to cool in the tins for about 10 minutes, remove the cakes from the tins and leave to cool completely on a rack. When the cakes are cooled remove the paper from the bottom.