Cut the tops off and remove the seeds and ribs from the peppers. Wash and set aside.
In a large bowl, combine the beef, rice, onion, one can of the tomato sauce, Worcestershire, garlic powder and salt and pepper. Stuff each pepper approximately 2/3 of the way full. Be sure to leave room for the rice to expand.
Stand the peppers up side-by-side in a plastic container the same size as or slightly smaller than your crockpot. Mix the remaining can of tomato sauce with the Italian seasoning and crushed red pepper and pour over the stuffed peppers.
Cover and freeze. When peppers are thoroughly frozen, remove from the container, wrap tightly in tin foil and then plastic wrap. Label and freeze up to six months.
Night Before Assembly:
Remove stuffed peppers from freezer and unwrap. Place in crockpot. Put crockpot in the refrigerator to allow the peppers to defrost overnight. (This is much easier if the pot from your crockpot is removable, but will work fine either way.)
Six hours before serving, place crock with peppers back into crockpot. Set heat to low and cook for at least six hours.