Pour 1/4 cup of the canned tomato liquid into a small saucepan. Add onions and green pepper and bring mixture to a boil. Cover and cook 15 minutes. Stir in remaining sauce ingredients, mixing well. Cover and cook 5 minutes. Remove from heat. To make filling, combine tofu ricotta and 3/4 cup "cheesy" sauce in a small bowl. Mix well. Cook spaghetti according to package directions. Drain. Run spaghetti under cold water to cool. Drain again. Place spaghetti in a large bowl and add oil or stock, egg replacer, and remaining "cheesy" sauce. Mix well. Preheat oven to 350 degrees. Lightly oil an 8-inch square baking pan or spray with a nonstick cooking spray. To assemble casserole: Spread spaghetti mixture evenly in prepared pan. Drop "cheese" filing by tablespoonfuls onto spaghetti. Spread filling over spaghetti, using the back of a spoon. Spoon sauce evenly over "cheese". Bake, uncovered, 35 minutes. Let stand 5 minutes before serving. From the files of DEEANNE