2 cups heavy cream
1 vanilla bean
1/2 cup sugar
4 egg yolks
additional white sugar for the caramelized top
Using a whisk, mix the egg yolks and sugar. Mix in the cream and the vanilla bean (which has been split open and seed scraped into mixture). In a heavy bottomed sauce pan, heat the cream mixture, whisking constantly until it reaches the consistency of melted ice cream. Very thick, but not lumpy. If lumps form, strain them out. Pour the custard into shallow custard cups and chill well. When cold, sprinkle the tops with white sugar, and caramelize this sugar using a propane blow torch.
This can be really be done best with the blow torch, as home broilers don't have the heat output necessary to make the hard caramel before the custard melts. The torch costs about $20 at the hardware store, and is well worth the investment.