Pour the cream into a saucepan and bring just to a simmer over medium heat.
Take off the heat.
If using a vanilla bean, slit it down the center lengthwise with a small knife.
Pry open the 2 halves with the point of the knife and lay the halves, on a cutting board.
Use the knife to scrape out the tiny black seeds and add them to the cream.
Put the pod in, too.
Cover and let steep for 10 minutes to flavor the cream.
Bring a teapot of water to a boil.
Separate the egg yolks from the whites.
You want only the yolks for this custard.
Keep going until you have collected all 5 yolks in the bowl.
Add the sugar and salt to the yolks and whisk for about 30 seconds, until the mixture turns a light yellow color and becomes thick.
Take the vanilla bean out of the pot and discard it.
Whisking the constantly, gradually pour about 1/4 of the hot cream in a thin stream.
Then pour in the rest of the cream.
Set 4 ramekins in a baking dish.
Divide the creme mixture among the ramekins.
Open the oven door and pull a rack out about halfway.
Put the baking dish on the rack and pour boiling water into the dish so that it comes about halfway up the ramekins.
(This water bath is mandatory: The idea is that the water remains a constant temperature, too low to scramble the eggs.
That way you don’t end up with a frittata.
) Push the rack back into the oven.
Repeat with a second rack if you are using 2 baking dishes.
Close the door.
Set timer for 30 minutes if using the 5-inch shallow molds, 40 minutes for the deeper 3-1/2-inch ramekins.
When the timer rings, pull out the oven rack and watch how the custard looks as it moves.
It should have begun to set up but still shake like Jell-O.
Stick a thin knife into the center of one of the custards.
The knife will not be clean when you pull it out but the mixture should be hot when you taste it.
If not hot, put the custard back in for 5 minutes.
If you’re not sure, take it out.
Careful - don't spill water baths.
Ladle as much of the hot water out as you can, then remove all 4 ramekins from the water bath.
Let cool for 20 minutes.
Cover with plastic wrap and refrigerate until completely cold; at least 2 hours or overnight.
When ready to serve, move one of the oven racks to the top position and heat the broiler to high (unless you’ve bought a blowtorch, in which case skip the oven instructions).
Unwrap the custards and put them on a baking sheet.
Sprinkle the top of each as evenly as you can.
If you have a blowtorch, fire it up and point it downward directly onto the sugar, moving it in a circular motion around each creme brűlée to burn the sugar to a nice dark brown.
If you’re using the oven, put the baking sheet under the broiler and broil until the sugar melts and caramelizes.
How long this takes will depend on your broiler and how close the custard is to the heat, but start checking at 30 seconds.
Let the custards sit at room temperature for a few minutes to cool and harden, and so your guests don’t burn the roofs of their mouths.
If one side caramelizes more quickly than the other, turn the custards for more even browning.
When you can smell the caramel and see that it has melted and hardened, take the custards out.