1. Cook pasta according to package directions, omitting salt and fat.
2. While pasta cooks, place flour in a small bowl, and gradually add milk, stirring with a whisk until well blended.
3. Cook bacon in a large saucepan over medium-high heat until crisp. Remove bacon from pan, reserving 1 teaspoon drippings in pan; crumble bacon, and set aside. Add garlic to drippings in pan; sauté 30 seconds. Add milk mixture, and cook over medium heat 4 minutes or until thick, stirring occasionally. Remove pan from heat; add Gruyère, salt, and pepper, stirring until cheese melts.
4. Drain pasta. Combine pasta, cheese sauce, crumbled bacon, basil, spinach, and tomatoes; toss. Sprinkle with Parmesan cheese.