Preheat your oven to 325°F (163°C).
In a medium saucepan, combine heavy cream, milk, and sugar. Add the scraped vanilla bean seeds and the pod. Heat until just steaming with bubbles at edges.
In a large spouted measuring cup, whisk egg yolks until smooth. Slowly add a few ounces of the hot cream to temper the eggs, whisking constantly.
Gradually add the remaining cream mixture to the yolks, whisking until fully incorporated.
Whisk in salt and white pepper.
Gently fold in the lump crab meat without breaking it up too much.
Stir in chives, dill, and lemon zest until evenly distributed.
Skim any foam off the top of the mixture to ensure a smooth custard surface.
Divide the mixture evenly between 6 ramekins. Place ramekins in a 9×13 baking dish.
Carefully pour hot water into the dish, filling halfway up the ramekins.
Bake for 30–35 minutes, until custards are set with a slight jiggle in the center.
Remove ramekins from the water bath and let cool to room temperature. Refrigerate for at least 3 hours or up to 3 days.
Before serving, sprinkle about 2 teaspoons of sugar over each custard. Use a blowtorch to caramelize the sugar until golden and crisp.
Serve immediately, or chill again for up to 1 hour for a cool custard and warm crust contrast.