Into a medium saucepan on medium heat, add heavy cream and heat until it just begins to simmer. Do not let it boil. Remove from heat and stir in the vanilla extract.
In a large bowl, whisk together the egg yolks, ¼ cup granulated sugar, and salt until the mixture becomes pale and thick, 2 to 3 minutes.
Slowly pour the warm cream into the egg yolk mixture, whisking constantly to prevent the eggs from cooking.
Using a fine mesh sieve, strain the custard mixture into a large measuring cup or bowl (to remove any egg that may have cooked).
Into 4 ramekins, divide the custard mixture evenly.
Place the ramekins in a baking dish.
Pour hot water into the baking dish until it reaches halfway up the sides of the ramekins.
Carefully transfer the baking dish to the preheated oven and bake for 35 to 40 minutes, or until the custards are just set but still slightly jiggly in the center.
Remove the ramekins from the water bath and cool to room temperature. Cover with plastic wrap and refrigerate for at least 2 hours, or until well chilled.
Just before serving, using the remaining ¼ cup granulated sugar, sprinkle a thin, even layer of sugar over the top of each custard (you may not use all of the sugar).
Use a kitchen torch to melt and caramelize the sugar until it forms a crispy, golden-brown crust. Alternatively, you can place the ramekins under a broiler set on high for 1 to 2 minutes, watching carefully to prevent burning.
Cool for a few minutes so the caramelized sugar can harden a bit before serving.
Notes
Leftover creme brulee will keep in the refrigerator, tightly covered, for 4 days. For the best texture, store without the sugar topping and torch just before serving.
If Already Brûléed: The top will soften in the fridge, so before serving, sprinkle more sugar and re-torch it to restore the crackle.