Boil a pot of salted water. Chop onions and parsley.
Brown beef, onion and garlic in a pan until crumbly.
Once cooked, drain the grease and place mixture in a large mixing bowl to cool.
Cook shells in boiling water for about 15 minutes. Drain and rinse when cooked.
Preheat oven to 400 degrees.
Once meat mixture is cool, stir in cheese, breadcrumbs, parsley, salt, pepper and egg.
Place 1/4 cup of sauce on the bottom of a 9x13 pan. Stuff the shells with the meat mixture.
Once all the shells are stuffed, cover with the remaining sauce and sprinkle with mozzarella cheese.
Bake at 400 degress for 25 minutes or until cheese is golden brown and sauce is bubbly.
Serve with garlic bread and your favorite red wine! Enjoy!