Lasagna Florentine

1 large onion, finely chopped
4 cloves garlic, minced
1 can (16 oz) unsalted tomatoes with liquid, chopped
1 can (6 oz) unsalted tomato paste
1/2 tsp oregano
1/8 tsp basil
1/8 tsp marjoram
6 C cooked spinach lasagna, prepared without fat or salt (about 10 oz uncooked)
1 lb fresh spinach, lightly steamed, chopped, and drained
2 C low-fat (1%) cottage cheese
1 C part-skim ricotta cheese
3 T grated Romano cheese
1 T minced fresh parsley
4 oz part-skim mozzarella cheese, shredded

Sauté onion and garlic briefly. Add tomatoes, tomato paste, and herbs. Simmer for 30 minutes. Mix cheeses (except mozzarella) with parsley. Spread a thin layer of tomato sauce in the bottom of a 9 x 13-inch baking pan. Layer with one-third the lasagna noodles, half the cheese, half the spinach, and one-third the tomato sauce. Repeat layers. Top with the remaining lasagna noodles and tomato sauce. Sprinkle with mozzarella. Bake at 350° for about 40 minutes.