Here's a delicious but simple-to-make pie that's not just for the holidays (although it's a terrific stand-in for pumpkin pie).
If you find canned sweet potato purée in your market, it will save you a lot of time; otherwise you'll need to peel, dice and cook enough sweet potatoes to yield 1-2/3 cups purée (about 2-1/4 lbs raw). The pie is best served the day it's made, but it can be cooled and refrigerated for up to 2 days.
Old World yams and New World sweet potatoes are indeed different vegetables. In the US today, the terms are often used interchangeably to describe popular varieties of red-skinned, orange-fleshed tubers with pointed ends. At Earthbound Farm we produce the Garnet and Jewel varieties, which are commonly called yams but are actually sweet potatoes. No matter what you call them, though, they're delicious!
Position a rack in the lower third of the oven and preheat to 425 degrees F.
Roll the pastry into an 11-inch circle and fit it into a 9-inch pie pan. Turn the overhanging dough under and flute or crimp the edges. Transfer the pie pan to a rimmed baking sheet.
Make the streusel topping: Place the sugar and flour in a small bowl and whisk to blend. Stir in the butter, mixing until crumbly. Add the pecans and stir to distribute. Set aside.
Place the sweet potato purée in a food processor or blender and add the eggs and spices. Process until smooth. Pour the mixture into the crust. Bake the pie for 15 minutes.
Reduce the oven temperature to 350 degrees F. Sprinkle the streusel topping over the pie. Continue baking until the filling is puffed and a knife inserted into the center of the pie comes out clean. Transfer the pie to a wire rack and cool completely. Serve at room temperature or refrigerate, covered, for up to 2 days.