Preheat oven to 325°.
Place the sweet potatoes in a large bowl. Add margarine, brown sugar, pecans, vanilla, flour and cinnamon and mix well. Beat in the egg.
Form the mixture into bite size balls and roll in crushed cornflakes.
Place the sweet potato balls on the baking sheet coated with nonstick cooking spray and bake for about 20 minutes. Serve with toothpicks.