Into a pot over medium heat, add Granulated Sugar (1 cup), yolks of the Egg (8), 1 tablespoon of zest from the Lemon (4), 3/4 cup freshly squeezed lemon juice, Salt (1/4 teaspoon), Vanilla Extract (1 1/2 teaspoon), and Butter (8 tablespoon). Cook, stirring, until mixture is smooth.
Continue to cook, stirring throughout, for about 5 minutes. Mixture should thicken slightly.
Pour the mixture through a strainer into a mixing bowl. Cover the bowl with plastic wrap, making sure the wrap touches the mixture on top. Let it rest for 30 minutes at room temperature.
Pour the mixture into a Graham Cracker Pie Crust (1). Cover it with plastic wrap, pressing it against the tart's surface. Place in the fridge to chill for at least 24 hours.
Smooth the top before serving. Decorate as desired.