Cook pasta, rinse and set aside Heat Oven to 350 degrees In a large skillet, brown meats and onion, breaking meat into small pieces; drain In a large bowl, stir together meat, eggs, bread crumbs, 1 cup mozzarella cheese, onion, mushrooms, garlic, oregano, salt and pepper.
Fill each shell with about 2 Tbl of meat filling.
Spread a thin layer of spaghetti sauce in the bottom of oven proof pan.
Place a single layer of shells on top of spaghetti sauce.
Cover shells with remaining sauce.
Sprinkle with remaining 1 cup Mozzarella cheese and Parmesan cheese.
Cover and bake 30 to 45 minutes or until hot and bubbly.