Preheat oven to 300°F. Line a roasting pan with a towel and place 4 ramekins on top, spaced apart.

Heat cream in a saucepan. Scrape seeds from the vanilla bean and add seeds and pod to the cream. Whisk in salt and 3 tablespoons sugar; bring to a boil. Remove from heat.

Whisk yolks and remaining 3 tablespoons sugar in a bowl until pale yellow and thick.

Add a little hot cream to the yolks, whisking constantly. Gradually add the rest of the cream. Strain through a sieve and discard the pods.

Skim foam from the custard and fill ramekins with it (about 3/4 cup per ramekin).

Pour boiling water into the roasting pan halfway up the ramekins. Cover with foil and bake until set around the edges (35-45 minutes).

Cool ramekins for 30 minutes, then refrigerate until cold (about 3 hours).

Before serving, sprinkle 1 tablespoon sugar on top of each custard. Burn with a kitchen torch until caramelized.

Alternatively, broil until golden brown, checking frequently (15-60 seconds).

Freeze for 5 minutes before serving.