In a medium saucepan, whisk together the egg yolks and sugar.
Add the lemon juice and switch to using a wooden spoon to stir.
Stir continually for 8-12 minutes on low: making sure mixture does not boil.
Your curd is done when it thickens and coats the back of the spoon.
Next: add butter and stir until butter is melted.
Add lemon zest and remove from heat.
Store in a jar then place in refrigerator