Line the base of a greased deep 20cm tin with baking paper.
Cream the butter and gradually add the sugar until the mixture is light and fluffy.
Gradually beat in the slightly beaten eggs, adding them one at a time, and beating until well-incorporated before adding the next.
Preheat your oven to 180C.
Sift the flour and salt together (you can do this a few times, which will help to make the cake lighter).
Gently fold the flour and salt into the creamed butter mixture, alternating the flour with the milk and lemon zest and juice being careful not to overwork the mixture.
Spread the mixture evenly in the prepared tins and bake for 40-45 minutes, or until cooked through (a skewer will come out clean).
Leave on a wire rack to cool completely.