Add all remaining ingredients except spaghetti -- 1 28 oz. can crushed tomatoes, 2 15 oz. cans tomato sauce, 2 6 oz. cans tomato paste, 1 cup beef broth, 1 cup water, 1 tablespoon dried basil, 1/2 teaspoon dried oregano, 1 teaspoon dried fennel, 2 teaspoons dried parsley flakes, 1 teaspoon onion powder, 1 teaspoon garlic powder, 2 tablespoons sugar, 1/4 teaspoon red pepper flakes, Salt and pepperto slow cooker and stir to combine.