01 - Preheat oven to 325°F. Arrange four 6-ounce ramekins in a large baking dish.
02 - In a saucepan, combine heavy cream, whole milk, and vanilla bean seeds or extract. Heat gently over medium until the mixture is just beginning to simmer, then remove from heat and allow to infuse for 10 minutes.
03 - In a mixing bowl, whisk together egg yolks, granulated sugar, and sea salt until mixture becomes pale and slightly thickened.
04 - Slowly add the warm dairy mixture to the egg yolk mixture, whisking continuously to temper and prevent curdling.
05 - Strain the combined mixture through a fine mesh sieve into a pitcher. Evenly pour into the prepared ramekins.
06 - Fill the baking dish with hot water until it reaches halfway up the sides of the ramekins, forming a water bath.
07 - Bake for 35 to 40 minutes, or until the custards are set but still slightly wobbly in the centers.
08 - Carefully remove the ramekins from the water bath. Allow to cool to room temperature, then refrigerate for a minimum of 2 hours, preferably overnight.
09 - Sprinkle each custard with an even layer of granulated sugar (about 1 to 2 teaspoons per ramekin). Caramelize with a kitchen torch until golden brown and crisp. Allow to stand for 2 minutes before serving.