Preheat the oven to 325°F.
In a medium saucepan, heat the heavy cream and salt over medium heat. Just before it simmers, turn off the heat and add the vanilla extract. Set aside.
In a small heat-proof bowl, whisk together egg yolks and ½ cup of sugar.
Use a ladle to pour some hot cream into the egg yolk mixture and whisk to temper the egg yolks. Add that mixture back into the hot heavy cream, whisking the entire time.
Pour the mixture into a liquid measuring cup and divide among 8 round ramekins. Place the ramekins in a large baking pan and pour boiling water halfway up the sides of the ramekins.
Bake until the edges are set, about 30–35 minutes. The centers should still be jiggly.
Remove the ramekins from the baking pan and cool at room temperature for at least an hour.
Cover each ramekin with plastic wrap, poke some holes in the top, and transfer to the fridge to cool for at least 4 hours.
Just before serving, sprinkle the remaining ¼ cup of sugar evenly over the tops.
Torch method: Use a kitchen torch to caramelize the sugar.
Broiler method: Place the ramekins on a baking sheet and broil on the top oven rack for 2–5 minutes, watching closely, until the sugar melts and turns golden. Rotate the sheet if needed.
Let the sugar harden for 1–2 minutes, then serve immediately.