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 15 minutes.
In a bowl, whisk together the egg yolks and ½ cup of granulated sugar until well blended.
Slowly pour the cream mixture into the egg yolk mixture, whisking constantly.
Strain the mixture through a fine sieve into a large measuring cup or bowl.
Divide the mixture among 4 ramekins and place them in a baking dish. Pour hot water into the dish until it reaches halfway up the sides of the ramekins.
Bake for 40-45 minutes, or until the custards are set but still slightly jiggly in the center.
Remove the ramekins from the water bath and let them cool to room temperature. Refrigerate for at least 2 hours.
Before serving, sprinkle ¼ cup of granulated sugar evenly over the tops of the custards. Use a blowtorch to caramelize the sugar until it forms a crispy top.