Preheat oven to 375 degrees F. Spray a 9x13-inch baking dish with nonstick cooking spray; set aside. Cook pasta shells according to package directions. Rinse with cold water, drain and set aside.

Add turkey and onion to a large skillet over medium-high heat and cook, breaking up meat, until turkey is cooked through and onion is tender. Add garlic and cook for an additional minute.

Add turkey mixture to a large mixing bowl and mix in 1 cup mozzarella cheese, ricotta, egg, Italian seasoning, salt and pepper.

Spread half the pasta sauce in prepared baking dish. Fill shells with turkey mixture (about 1 Tablespoon of mixture per shell) and place in baking dish. Once all shells are filled, pour remaining sauce on top of the shells. Top with remaining cup of mozzarella cheese and cover pan with foil.

Bake for 20 minutes then remove foil and bake for an additional 10 minutes or until cheese is melted. Garnish with fresh parsley before serving.