Preheat oven to 325°F (160°C).
In a saucepan, heat heavy cream and vanilla over medium heat until warm, but not boiling. Remove from heat and let it sit for a few minutes.
In a mixing bowl, whisk together egg yolks, sugar, and salt until pale yellow.
Slowly pour the warm cream into the egg mixture, whisking constantly to avoid curdling the eggs.
Strain the mixture through a fine mesh sieve into a clean bowl.
Pour into ramekins and place them in a large baking dish.
Fill the dish with hot water halfway up the sides of the ramekins to create a water bath.
Bake for 35–45 minutes or until custards are just set but still slightly wobbly in the center.
Remove from oven, let cool, then refrigerate for at least 4 hours (or overnight).
Just before serving, sprinkle 1 teaspoon of sugar over each custard. Use a kitchen torch or broiler to caramelize the sugar until golden and crisp.
Let the topping cool for 2–3 minutes before serving.