Cook beef, onion and garlic in a large skillet over medium-high heat, stirring beef until crumbles and is no longer pink, drain. Stir in water, tomato paste, bouillon, and oregano, simmer over medium heat about 30 minutes.
Stir in the cottage cheese, and one cup mozzarella, Parmesan cheese and egg in a medium bowl, mix well. Stuff shells with cheese mixture, arrange in a greased 13x9" baking pan. Pour beef mixture over shells. cover and bake at 350 degrees fo 40 -45 minutes. Uncover and sprinkle with remaning mozzarella cheese. Bake 5 minutes more until cheese melts.