Toast the nuts.

Preheat the oven to 275F.

Whisk the egg yolks in a medium bowl until pale.

Whisk in the light brown sugar until dissolved.

Whisk in the pumpkin puree, sour cream, heavy cream, cinnamon, ginger, and five-spice powder.

Place six standard-size flan dishes in a baking pan.

Divide the custard mixture among the dishes.

Sprinkle the toasted nuts over the custard.

Pour warm water into the pan to come halfway up the sides of the dishes.

Bake in the oven for 35 to 40 minutes, or until the center of each custard still jiggles slightly.

Remove from the oven and lift the dishes from the hot water.

Let cool briefly, then refrigerate for at least 2 hours or up to 2 days.

When ready to serve, place the dishes on a baking sheet.

Evenly sprinkle 1 tablespoon oven-dried brown sugar or raw sugar over each custard.

Using a hand-held blowtorch, caramelize the sugar.