Preheat oven to 425° In a large bowl, combine the first 8 ingredients; beat until smooth. Line a 9-in. pie plate with pastry; trim and flute edges. Pour filling into crust.
Bake 15 minutes. Reduce heat to 350°. Bake 45-50 minutes longer or until crust is golden brown and top of pie is set (cover edges with foil during the last 15 minutes to prevent overbrowning if necessary). Cool on a wire rack for 1 hour. Refrigerate overnight or until set.
If desired, serve with whipped cream and sprinkle with cinnamon.