Prepare the lemons by zesting 2 teaspoons and juicing 1/2 a cup, put aside until needed.
In a pot whisk together the lemon juice, lemon zest, sugar, and eggs.
Place the pot over the heat and add the butter. Whisk gently and occasionally while heating to melt the butter.
When the butter has melted whisk continually until it starts to bubble, then turn down to a gentle simmer and continue to whisk over the heat for 6 minutes until the mixture has thickened.
Take off the heat and continue to whisk while cooling for 4 minutes. Transfer to a jar or bowl. Chill for at least 1 hour or until needed.