Preheat oven to 325 degrees F.

Place pumpkin in a saucepan over medium heat.

Stir frequently until the pumpkin thickens and caramelizes (about 10 minutes).

Whisk egg yolks and granulated sugar in a large bowl.

Set aside the egg yolk mixture.

Add heavy cream, whole milk, light brown sugar, vanilla bean seeds, cinnamon, nutmeg, and ginger to the caramelized pumpkin.

Whisk until well integrated.

Bring to a simmer over medium heat, then remove from heat.

Add sea salt (and vanilla extract, if using).

Remove the vanilla bean and reserve it for another use.

Slowly whisk 1/4 cup of the hot pumpkin/cream mixture into the eggs to temper them.

Add the remaining pumpkin/cream mixture in a slow, steady stream, whisking continuously.

Divide the mixture among ramekins or creme brulee dishes.

Place ramekins in a large roasting pan.

Add enough hot water to the pan to come halfway up the sides of the ramekins.

Cover the pan with foil and pierce it in several places.

Bake for about 30 minutes, then lift off a corner of the foil to release steam.

Re-cover the pan and bake for 10 to 15 minutes longer, or until the custards are just set in the center.

Chill custards until cold (about 4 to 6 hours).

Right before serving, sprinkle a few grains of sea salt on top of each chilled custard.

Sprinkle 2 to 3 tsp of raw sugar in a thin, even layer.

Use a kitchen torch or preheated broiler to caramelize the sugar.