• 100 g butter
• 220 g sugar
• grated zest and juice of 4-5 lemons
• 4 eggs plus two extra egg yolks

Melt the butter in a saucepan add all the ingredients including the beaten eggs. Stir constantly over a very low heat until the mixture thickens (about 15 minutes) Be patient as if the element is too hot or you stop stirring, the eggs may scramble.
This makes about 500 gm and keeps for about a week in the fridge.