Adjust oven rack to the lower-middle position and preheat oven to 300°F (150°C).

In a medium saucepan, combine 1 cup cream, granulated sugar, and salt. Scrape vanilla seeds into the pan and add the pod. Bring to a simmer, stirring to dissolve sugar. Remove from heat, cover, and let steep 15 minutes. (If using extract, skip steeping and add later.)

Stir in the remaining 1 cup cream to cool the mixture slightly.

In a bowl, whisk yolks until smooth. Gradually whisk in the warm cream mixture until fully combined. Strain through a fine-mesh sieve into a large measuring cup or pitcher.

Arrange 6 ramekins (4–5 oz each) in a baking dish lined with a kitchen towel. Divide custard evenly among them.

Place the baking dish in the oven and carefully pour boiling water into the pan until it reaches two-thirds up the sides of the ramekins.

Bake until custards are set but still slightly jiggly in the center, 25–35 minutes depending on ramekin depth.

Remove ramekins from water bath and let cool to room temperature, about 2 hours. Cover with plastic wrap and refrigerate until cold, at least 4 hours or up to 4 days.

Just before serving, sprinkle 1–1.5 teaspoons sugar evenly over each custard. Caramelize using a kitchen torch, sweeping the flame evenly until the sugar is melted and golden brown. (Alternatively, place under a broiler or use a heated spoon.)

Let the sugar harden for a minute before serving.