Preheat your oven to 350°F (175°C). Prick the bottom and sides of the thawed pie crust with a fork. Bake for 15 minutes, or until lightly golden. Set aside.
Increase the oven temperature to 425°F (220°C).
In a blender or food processor, combine the cooked purple sweet potato, coconut milk, melted butter, sugar, egg, cinnamon, allspice, vanilla, and salt. Blend until the mixture is completely smooth. If needed, scrape down the sides to ensure everything is incorporated.
Pour the smooth purple filling into the par-baked pie crust and spread it evenly with a spatula.
Bake at 425°F (220°C) for 15 minutes. Then, reduce the oven temperature to 350°F (175°C) and continue baking for another 15-20 minutes. The pie is done when the filling is set and does not jiggle in the center.
Remove the pie from the oven and let it cool completely on a wire rack. Once at room temperature, cover the pie and refrigerate for at least 6 hours, or preferably overnight, to firm up.
Just before serving, make the topping. In a chilled bowl, use a hand mixer or stand mixer to whip the cold heavy cream, maple syrup, and vanilla until soft peaks form. Be careful not to over-whip.
Slice the chilled pie and serve each piece with a dollop of maple whipped cream and a sprinkle of chopped pecans.