Heat oven to 350°. Combine pumpkin pie filling, candied yams, light-brown sugar, pumpkin pie spice, salt, cream, butter, and eggs in the bowl of a food processor, then process until smooth. Line a 10-inch pie pan with the crust and fill with the pumpkin-sweet potato mixture. Fasten aluminum foil around the exposed pastry edge to prevent it from burning. Bake 1-1/2 hours. Remove from the oven and set aside at least 20 minutes.
1 large egg
1/2 cup dark corn syrup
1/2 teaspoon vanilla extract
1 cup chopped pecans
Mix together the first three topping ingredients, layer on top of the cooled pie, then distribute pecan pieces evenly. Return to the oven 30 minutes. Cool on a rack at least 15 minutes before serving.