This is a filling dish. This was orginally a stuffed manicotti recipe, however I made a few adjustments, and then stuffed shells. You can use this recipe for stuffed shells or stuffed manicotti. My family loved this, it goes great with a salad and garlic bread. Or great to take to a potluck or office party.
In a large saucepan, saute onion and green pepper in olive oil until tender. Add garlic; cook for abount 1 minute. Stir in remaining ingredients; and bring to a boil. Reduce heat; cover and simmer for about an hour, stirring occationally. Uncover, and simmer for 10-15 minutes or until thickened.
While that is cooking, for the stuffing; brown the beef and onion in a skillet. Then add garlic; and cook for another minute. Drain and cool slightly.
Squeeze spinach to remove excess water; add to skillet with 1/2 cup Parmesan cheese, eggs oregano, salt & pepper. Mix well. The sauce makes about 4 cups, you will only need about 2 1/2-3 cups for this recipe. You can save the reaminder for another recipe (you can also freeze for a starter sauce).
You will take some of the sauce, a cup or so and into a 13 8 9 baking dish. Stuff the shells with the meat filling, arrange over the sauce. Pour another 1 1/2-2 cups of sauce over the stuffed shells. Sprinkle with the mozzarella and the remaining Parmesan cheese.