Preheat your oven to 325°F (160°C).
In a saucepan, heat the heavy cream and vanilla bean until just boiling. Remove from heat and let it sit for a few minutes.
In a mixing bowl, whisk together the egg yolks and ½ cup of sugar until pale and thick.
Slowly pour the hot cream into the egg mixture, whisking constantly.
Strain the mixture through a fine sieve into a clean bowl.
Divide the mixture among the ramekins.
Place the ramekins in a baking dish and fill the dish with hot water halfway up the sides of the ramekins.
Bake for 40-45 minutes, until the custard is set but still slightly jiggly in the center.
Remove from the oven and let cool to room temperature, then refrigerate for at least 2 hours.
Before serving, sprinkle the remaining sugar evenly over the tops of the custards and caramelize with a blowtorch until golden brown.