Heat the cream in a pot with the basil. Stir regularly, especially as it gets warmer, to avoid forming a skin on top. When it is simmering, but before it begins to boil, remove from heat and add the vanilla extract.
In a small bowl, with a fork, cream the egg yolks and sugar until smooth. Try not to incorporate much air into the mixture.
Place the 1 tbsp lemon curd in the bottom of each of four ramekins and spread evenly.
SLOWLY drizzle cream into eggs, continuing to beat with the fork. If you pour too quickly, the hot cream will cook the egg. Again, try not to incorporate any air as you mix.
Split the raw custard evenly between the ramekins. Place into a baking pan. Pour water into the pan (making sure not to splash any water into the ramekins) until the water goes halfway up each ramekin.
Carefully transfer to the oven and bake about 30 minutes. Actual time will depend on the shape of the ramekin. Custard is done when it is set but still a little jiggly.
Remove from oven and allow to cool to room temperature. Then cover with plastic wrap and chill in the fridge. Chill at least a couple hours. You can keep this in the fridge several days if you like.
Just before serving, sprinkle with a couple teaspoons of sugar. Use a kitchen torch to melt and caramelize the sugar. If you don't have a kitchen torch you can use the broiler in your oven, but be careful, the sugar burns easily!