Adjust oven rack to middle position and preheat the oven to 300°F. Add heavy cream, vanilla bean seeds, and pod to small saucepan. Heat over medium-high heat, stirring frequently until little bubbles form around sides of the cream in the pot.
Combine egg yolks and 1/3 cup sugar in bowl of stand mixer fitted with whisk attachment. Whisk on medium speed until pale yellow and yolks fall off of whisk in ribbons, about 2 minutes, scraping bowl as necessary. With mixer running on medium-low speed, slowly add hot cream mixture. Whisk until thoroughly combined.
Place a folded kitchen towel (or a few paper towels) on the bottom of a roasting pan or glass baking dish large enough to hold six 6-ounce ramekins. Place ramekins on top of towel and ladle custard base evenly between them. Pour hot water into baking dish until it comes 1/2 way up sides of ramekins.
Bake until custard is set but still jiggles in center, about 40 minutes. Remove from oven and allow to cool to room temperature without removing ramekins from water bath. Once cool, cover ramekins in plastic and refrigerate until set, at least 4 hours, and up to overnight.
To serve, sprinkle each ramekin with 1 teaspoon sugar. Brown with kitchen torch, and serve immediately.