Cook shells according to box directions for 1/2 of the recommended time. Drain in a colander and run cold water over them to stop the cooking process. Drain again.
In large mixing bowl, place all other ingredients and stir until well blended.
Take shells, one at a time, and stuff with a large spoonful of cheese. See photos in post for demonstration of how I do this.
Place stuffed shells on a greased or wax paper lined baking sheet. Once all shells are stuffed, place sheet in freezer for about an hour, or until shells are frozen hard. Remove shells and put them in zipper seal freezer bags and return to freezer for longer term storage.