beat whipped topping mix with 1 cup milk and the vanilla, using large mixer bowl; beat at high with electric mixer about 6 min. Or until topping thickens and forms peaks. Add remaining milk and the pie filling mix; blend at low. Beat at high for 2 min., scraping bowl occasionally. Spoon into pie shell. Chill at least 4 hours. Recipe from unknown, a scrap of paper in my possesion for years.