Over medium low heat in a saucepan add lemon juice, zest and honey
Stir and heat until the honey is fully dissolved and incorporated into the lemon juice
In a separate bowl whisk your two eggs together well
Slowly drizzle the lemon honey mixture from the saucepan into the bowl while whisking all together
Whisk for about a minute
Then using a fine mesh strainer, strain the mixture back into the saucepan
Continue to constantly whisk and heat until it starts to thicken, about 5-7 minutes
As soon as it starts to simmer / bubble you know you've done it long enough
Add your vanilla, give it a quick stir and take it off the heat
Pour into a glass jar, cover, put into the fridge and you're done
Wait for it to cool and it should be all set in just a couple of hours.