This sweet treat comes from Eduardo Braniff, of New York City. When refrigerating, cover first with a paper towel (over custards, not touching) then with plastic wrap. The towel absorbs moisture and keeps the custards free of droplets.
Preheat oven to 325 degrees, with rack in the center. In a medium saucepan, whisk together cream, milk, syrup, and pumpkin. Bring to a simmer over medium heat. Meanwhile, in a large bowl, whisk together yolks, cinnamon, nutmeg, and salt.
Whisking constantly, gradually add hot cream mixture to the yolk mixture. Strain through a fine-mesh sieve into a large liquid measuring cup (for easy pouring).
Divide mixture evenly among six 6-ounce ramekins or custard cups. Line the bottom of a 9-by-13-inch baking pan with a kitchen towel; place ramekins on top.
Place in oven, and pour enough boiling water in pan to come halfway up sides of cups. Cover pan tightly with foil. Bake until custard is set and a knife inserted in center comes out clean, 40 to 45 minutes. Let cool completely, then refrigerate, covered first with paper towel and then with plastic wrap, for at least 2 hours or up to overnight.
Baking in a water bath helps the custards cook evenly; and lining the pan with a dish towel keeps the bottoms from scorching.