Preheat the oven to 375 degrees. Place the sweet potatoes on a baking sheet and drizzle with olive oil. Season the potatoes with salt and pepper and place in the oven.
Roast the sweet potatoes for 1 to 1 1/2 hours or until the potatoes are fork tender. Remove the potatoes from the oven and cool. Remove the skin from the sweet potatoes.
In a mixing bowl, whisk the sweet potatoes, molasses, spices, eggs, cream and 1 teaspoon vanilla together. Pour the filling into the unbaked pastry shell. Spread the pecan pieces evenly over the sweet potato filling. In a mixing bowl, whisk the remaining ingredients together. Pour the topping over the pecans. Bake for about 1 hour or until the filling and topping set. Cool for 10 minutes before slicing. Garnish with whipped cream, chocolate sauce, fresh mint sprigs, and powdered sugar.