Place cookie sheet on oven rack. Heat oven to 425°F. Place sweet potatoes in food processor; cover and process until smooth. In large bowl, mix sweet potatoes and remaining filling ingredients with wire whisk until smooth; pour into frozen pie crust.
Bake on cookie sheet 15 minutes. Reduce oven temperature to 350°F; bake 20 minutes longer. Meanwhile, in small bowl, mix streusel ingredients. Carefully sprinkle streusel over filling. Bake 10 to 15 minutes longer or until knife inserted in center comes out clean and streusel is golden brown. Cool completely, about 3 hours.
Serve pie with sweetened whipped cream. Store covered in refrigerator. 8 servings.