Preheat the oven to 180˚C. Grease a 20cm round cake tin or a 22cm loaf tin and line the base with baking paper.
Cream the butter and sugar until light and fluffy, then add the lemon zest and the eggs one at a time, beating well after each addition.
Sift the dry ingredients together and fold through the creamed mixture in about three lots, alternating with the milk. Scoop the mixture into the prepared tin and level the top.
Bake for about 40 minutes or until the cake springs back when lightly touched.
While the cake is cooking make the syrup by stirring the lemon juice and sugar together then set aside until the cake is ready.
Leave the cake in the tin on a wire rack and spoon over the lemon syrup. It will soak in a little and run down the sides of the cake, leaving a thin crust of sugar on the top. Finish cooling in the tin, then turn out carefully.