How to Make It
Preheat oven to 400°F with rack in bottom position. Fit piecrust inside a 9-inch pie plate; fold edges under, and crimp. Fill crust with pie weights. Bake in preheated oven on bottom rack for 12 minutes. Remove pie weights. Continue baking until surface is just dry, about 5 minutes. Remove from oven; reduce oven temperature to 350°F.
Whisk together sweet potatoes, coconut milk, sugar, butter, eggs, vanilla, cinnamon, and salt in a bowl; pour into prepared crust. Bake at 350°F until just set, 40 to 45 minutes. Let cool completely on a wire rack, about 2 hours.
Dollop center of cooled pie with whipped cream; sprinkle with coconut.
To make mashed sweet potatoes: Wrap unpeeled sweet potatoes individually in aluminum foil. Arrange on a baking sheet, and bake at 400°F for 1 hour. Let cool 15 minutes. Remove and discard sweet potato skins. Process sweet potato flesh in a food processor until smooth, about 1 minute.