This recipe is from Jean's Grandmother's Recipe Book of 1934.

500gm granulated sugar
200gm butter
4 beaten eggs
rind and juice of 3 lemons

Melt butter in a saucepan and add the other ingredients. Heat, stirring all the time until the mixture starts to thicken. (Take care, if heated too quickly can scramble the eggs giving white bits in the curd.) Remove from the heat and allow to cool.
Bottle, keep in a fridge. Will keep for about two months.