In a saucepan combine heavy cream, granulated sugar, vanilla extract and lemon zest
Stir over medium heat and bring to a gentle simmer for 4 minutes. DO NOT LET BOIL
Remove from heat and let cool for 3 minutes
Add lemon juice and stir to thicken. As it mixes and cools the mixture will begin to thicken up
Pour into lemon halves (if you have extra mixture pour into a ramekin)
Let chill in the fridge for at least 45 minutes
