Preheat oven to 350 degrees. Spray 9-inch pie pan with non-stick cooking spray.
In a medium-sized mixing bowl, mix cream cheese and butter until combined. Add in flour and mix until the dough starts to clump together. If necessary, knead together to form a ball, and then press the dough down into the pie pan, covering the bottom and the sides of the pan.
Peel the sweet potatoes and cut up into one-inch chunks. Place in a pot with boiling water just covering the potatoes, and cook until fork-tender. Puree the cooked sweet potatoes in a food processor to get smooth consistency.
In a large mixing bowl, combine mashed sweet potatoes and remaining ingredients, and stir to incorporate. Pour into pie shell, and bake for 60 minutes.
Allow pie to cool, and serve topped with whipped cream.