Heat oven to 375 degrees. Cook pasta according to package directions; drain.
Meanwhile in a large skillet, cook meat and onion until meat is thoroughly cooked and onion is tender; drain. In a large bowl, stir together meat mixture, mozzarella cheese, 1/4 cup parmesan cheese, eggs, bread crumbs, parsely, italian seasoning and adobo seasoning.
In a 13x9x2 inch baking dish, spread 1/2 cup spaghetti sauce. Fill each cooked shell with 1-1/2 level tablespoons meat filling; layer one half filled shells in prepared dish. Spread 1 1/4 cup spaghetti sauce evenly over shells; layer remaining filled shells over sauce. Spread remaining spagehtti sauce over shells; sprinkle with remaining parmesan cheese. Cover with foil; bake 40 minutes or until hot and bubbly.