Sift the flour and baking powder into a bowl and then add the butter, the sugar and the salt. Mix together. I used my fingers, a bit like making pastry, until it was like fine breadcrumbs.
In another bowl add the milk to the eggs and whisk together. Then add this mixture to the first bowl, along with the lemon juice and zest. Whisk everything together.
Put the cupcake paper cases into cupcake trays and fill each one halfway with the mixture.
Bake for about 20-25 minutes at about 180C.
Ideally use a kitchen aid to beat the sugar and icing sugar together. If you don't have one you can cream them together instead. Add a third of the icing sugar to the butter at a time. Add the lemon zest and juice and mix in well.
When the cupcakes have cooled, either spread the icing on top or use a piping bag.
Nutritional information is approximate and a guideline only.