Preheat oven to 325°F (160°C). Arrange six 4-ounce ramekins in a large baking dish.
In a medium saucepan, heat the heavy cream and 0.5 cup of granulated sugar over medium heat until the sugar dissolves and the cream is just simmering. Do not boil.
In a separate bowl, whisk together the egg yolks, vanilla extract, and salt.
Temper the egg yolks by gradually whisking about half of the hot cream mixture into the yolks. Then, pour the tempered egg yolk mixture back into the saucepan with the remaining cream.
Cook the custard mixture over low heat, stirring constantly, until it thickens enough to coat the back of a spoon. Do not let it boil.
Strain the custard through a fine-mesh sieve into the prepared ramekins.
Pour hot water into the baking dish around the ramekins, filling it halfway up the sides of the ramekins. This creates a water bath for even cooking.
Bake for 30-40 minutes, or until the edges are set but the centers are still slightly wobbly.
Remove the ramekins from the water bath and let them cool completely on a wire rack. Then, cover with plastic wrap and refrigerate for at least 4 hours, or preferably overnight.
Just before serving, sprinkle about 1-2 teaspoons of granulated sugar evenly over the top of each custard. Using a kitchen torch, caramelize the sugar until it forms a hard, glassy crust. Let sit for a minute before serving.
Notes
For best results, ensure your ramekins are completely dry before sprinkling the sugar for torching. This prevents the sugar from melting unevenly.