Put the lemon zest, sugar, and butter in a glass or metal bowl. Put the bowl on top of a saucepan with boiling water because we will be using the bain marie-method. Make sure that the fire is on medium heat. Allow the butter to melt and stir the mixture until well combined.
Once well mixed, add the lemon juice and mix. Then add the eggs.
Now we wait. Make sure that there’s enough water in the saucepan and keep stirring the mixture. It will slowly start to thicken. Once it has the texture of yoghurt you’re done. I’d say it takes around 25-35 minutes.
When it has reached the right texture, put the lemon curd in another bowl to cool down. While it cools down it will thicken even further.
When the lemon curd has completely cooled down, it’s time to put it in a jar!