TO PRE-BAKE PIE SHELL: Preheat the oven to 375 degrees F. Set the pie shell on a baking sheet, prick the bottom and bake it for 10 minutes. Remove and set aside to cool. (If the bottom balloons up a bit, just prick it with a fork and it will settle down.)
TO MAKE FILLING: In a mixing bowl, with a wooden spoon, blend the cream cheese with 1 of the eggs and 1/4 cup of the sugar. In a food processor puree the remaining eggs with the sweet potatoes, remaining sugar, salt, ground cinnamon, ginger, nutmeg and half and half. Spread the cream cheese mixture on the bottom of the pie shell then spoon the sweet potato filling on top. Bake for 30 minutes.
FOR TOPPING: While the pie is baking, in a bowl combine the oats with the pecans, flour, cinnamon and sugar and toss until blended. Drizzle the butter over the top and with your fingers mix together. Sprinkle this mixture over the pie and bake for 30 to 40 minutes longer or until the filling has set. Remove the pie from the oven and cool to room temperature on a rack. If desired, serve with vanilla ice cream or whipped cream.
