Whisk yolks and sugar together until thick and pale yellow. Add cream and vanilla and mix until blended.
Strain and skim, then divide among 6 ramekins and place in a baking dish / water bath (in a baking dish, make sure water is half way up the sides of the ramekins... this allows moisture to flow through the oven and keep the custards soft).
Bake for 40-50 minutes, until the outside edges are set and the center is still loose. Remove from oven and cool in water bath.
Chill at least 2 hours or up to 2 days. When ready to serve, sprinkle sugar to cover the entire surface of each custard. Fire with a hand held torch until caramelized.