- Preheat oven to 300 degrees.
- In a medium saucepan, heat cream, milk, cinnamon stick, nutmeg, and ginger over medium heat, simmering to infuse flavors. Let stand for 15 minutes; remove cinnamon stick.
- In a large bowl, whisk egg yolks and granulated sugar together. Whisking constantly, gradually add hot cream mixture, followed by pumpkin purée.
- Divide mixture among 4 ovenproof ramekins and place in a hot water bath. Place on the center rack of preheated oven and cook for 30−45 minutes—custard should be almost set but slightly jiggly in the center. Remove ramekins from water bath and cool for 20 minutes.
- Tightly wrap each ramekin with plastic, being careful not to touch custard with the wrap, and refrigerate overnight.
- To serve, unwrap custards and place a thin, even layer of sugar on top of each. Caramelize sugar with a blowtorch. Let stand for 1 minute and serve.