Spinach Stuffed Shells
["2 Tbsp. salad oil", "1 small onion, diced", "1 (28 oz.) can tomatoes", "1 (6 oz.) can tomato paste", "2 tsp. brown sugar", "1 tsp. oregano leaves", "1 tsp. salt (optional)", "pepper to taste", "1 (12 oz.) pkg. jumbo macaroni shells", "2 (9 or 10 oz.) pkg. frozen creamed spinach in boilable bag", "1 (15 or 16 oz.) container Ricotta cheese (2 c.)", "1 (8 oz.) pkg. Mozzarella cheese, shredded", "1/4 c. Parmesan cheese", "1/4 c. fresh parsley"]
["About 1 1/2 hours before serving:", "In a 3-quart saucepan, over medium heat, in hot oil, cook onion until tender, stirring often. Add tomatoes with their liquid, tomato paste, brown sugar, oregano, 1 teaspoon of salt and 1/4 teaspoon pepper, stirring to break up tomatoes.", "Over high heat, heat to boiling.", "Reduce heat to low.", "Cover and simmer 20 minutes to blend flavors."]
["salad oil", "onion", "tomatoes", "tomato paste", "brown sugar", "oregano", "salt", "pepper", "jumbo macaroni", "frozen creamed spinach", "Ricotta cheese", "Mozzarella cheese", "Parmesan cheese", "fresh parsley"]