Step 1

Preheat oven to 400° F. Adjust oven rack to lowest position, and place rimmed baking sheet on the rack.

Step 2

Whisk cream, milk, eggs, yolks, and vanilla together in medium bowl, and set aside.

Step 3

Combine pumpkin puree, yams, sugar, maple syrup, ginger, cinnamon, nutmeg, and salt in large heavy-bottomed saucepan; bring to sputtering simmer over medium heat, 5 to 7 minutes. Continue to simmer pumpkin mixture, stirring constantly and mashing yams against sides of pot, until thick and shiny, 10 to 15 minutes.

Step 4

Remove pan from heat and whisk in cream mixture until fully incorporated. Strain mixture through fine-mesh strainer set over medium bowl, using back of ladle or spatula to press solids through strainer. Re-whisk mixture.

Step 5

Place pie crust in pie plate and carefully place plate on the preheated baking sheet. Pour the filling into the pie crust, and bake for 10 minutes at 400° F. Without taking the pie out of the oven, reduce the heat to 300° F, and continue baking until edges of pie are set (instant-read thermometer inserted in center registers 175° F), 20 to 35 minutes longer. The center 2 inches of the pie should look firm but jiggle slightly; the pie finishes cooking with residual heat.

Step 6

Transfer to wire rack and cool to room temperature and not in the refrigerator to ensure that the filling sets, 2 to 3 hours. Cut into wedges and serve at room temperature or chilled with whipped cream.