1. Preheat broiler to high.
2. Cook pasta according to package directions, omitting salt and fat; drain.
3. While pasta cooks, place tomatoes on a jelly-roll pan lined with foil. Broil 8 minutes or until tomatoes are beginning to blacken.
4. While tomatoes cook, heat a large saucepan over medium-high heat. Add canola oil to pan; swirl to coat. Add diced shallots, minced garlic, and thyme; sauté 2 minutes or until tender, stirring frequently. Add tomato paste; cook for 2 minutes, stirring occasionally. Add flour; cook 1 minute, stirring constantly. Stir in milk, black pepper, and salt; bring to a boil. Cook 4 minutes or until thick and bubbly, stirring frequently. Remove from heat. Add spinach, stirring constantly until spinach starts to wilt. Add shredded cheddar cheese, and stir until smooth. Stir in cooked pasta. Top with the roasted tomatoes.