Preheat the oven to 350°F. Lightly spritz a 9-inch deep dish pie pan with cooking spray. Press the pie crust firmly into the pie pan. Prick the bottom of the pie crust with a fork. Place onto a baking sheet and into the oven to bake for 7 minutes. Set aside.
In a medium mixing bowl, whisk together sweet potato puree, cream, granulated sugar, brown sugar, eggs, pumpkin pie spice, vanilla and salt . Mix until fully combined.
Pour custard into crust. Place into the oven and bake for 30 minutes.
Meanwhile, in a small mixing bowl, mix together vanilla wafer crumbs, granulated sugar and cinnamon. Cut butter into the mixture using a pastry blender or two forks until it resembles coarse crumbs. Mix-in the chopped pecans and English toffee bits by hand.
After baking for 30 minutes, sprinkle the pecan-crunch streusel over the top of the custard. Continue to bake for an additional 30 minutes until the custard is set when gently shaken and the pecan-crunch streusel is golden. Cover the edge of the crust with aluminum foil to prevent over-browning, if needed.
Cool the pie to room temperature then chill completely before cutting. Overnight is ideal. Serve with a dollop of fresh whipped cream, if desired.
Notes
Pumpkin pie spice contains varying amounts of cinnamon, ginger, nutmeg, allspice and cloves. It brings seasonal flavor to this sweet potato pie. You can use all cinnamon, if desired.
If you'd like to make your own sweet potato puree for the filling:
Bake sweet potatoes with the skin intact in a 375°F oven for around an hour or until fork tender.
Allow them to cool a bit, then slice and using a tablespoon scoop out the flesh.
Puree the flesh in a stand blender or using a hand mixer and cool then proceed with the recipe.