Preheat your oven to 325 °F (160 °C) and set a pot with water over medium heat (for the water bath).
Transfer the egg yolks, the sugar, the vanilla extract and the salt to a large bowl and whisk to combine.
Heat the cream until almost boiling and slowly add it to the egg yolk mixture whisking continuously until incorporated.
Divide the cream mixture between 6 ramekins (you don't want them to be full), place them inside a baking pan and fill the baking pan with boiling water about 1 ¾ inches deep (this is the water bath).Bake in the middle rack of the oven for 30-35 minutes or until the surface of the cream is set and the middle is still jiggly.
Wait until the cream is cool, cover with plastic wrap and chill in the fridge (at least 4 hours or overnight).
Just before serving, sprinkle each ramekin with 1 tablespoon sugar and burn it with a torch. Repeat this step for a double-layer sugar crust.Serve chilled or at room temperature.
Notes
The amount of sugar is enough to give the cream a nice taste without being overly sweet. If you like things sweeter, you can add a couple more tablespoons.
If you use real vanilla pod, cut it in half lengthwise, scrape the seeds and add them to cream before boiling it. If you use pure vanilla bean extract or paste, add it to the egg yolks. If you use vanilla sugar, you don't have to use additional vanilla flavoring.
Add the hot cream to the yolk mixture gradually, otherwise you risk cooking the yolks.
When pouring the cream into the ramekins, it's best to pass it through a fine sieve. It will catch any lumps from the yolks and will reduce any air-bubbles that may end up on the surface of the cream. Break any remaining bubbles with a toothpick. Don't fill the ramekins more than 2 inches in height.
Cooking time can vary depending on the size of the ramekins.
..Sous vide instructions:For the sous vide, you don't have to heat the cream, but if you use a vanilla pod instead of vanilla extract, heating it will infuse the custard better. Use small mason jars (5-6 oz capacity) or any other jars that can seal airtight. Don't leave too much empty space inside the jars. The lids should be closed well but not very firmly. Cook at 176 °F (80 °C) for 1 hour.