Preheat oven to 325 degrees. In a heavy saucepan, whisk together half and half, maple syrup, and pumpkin. Bring to a simmer over medium heat.
In a large bowl, combine egg yolks, cinnamon, nutmeg, and salt.
Slowly add hot pumpkin mixture to egg yolk mixture, whisking constantly. For easy pouring, transfer to a large measuring cup with a pouring spout.
Set out six ramekins and divide pumpkin mixture between them. Place ramekins in a 13 x 9-inch baking dish, then carefully pour hot water into the space between ramekins until it reaches halfway up their sides.
Cover dish tightly with aluminum foil and bake 40-50 minutes, or until a knife inserted in the center comes out clean. Chill at least two hours before serving. Dollop with whipped cream, if desired.