Preheat oven to 425 F. Place tomatoes, onion, garlic, and pine nts together on an oven tray. Gently toss to combine. Roast, tossing once, for 20 minutes or until tomatoes are tender.
Meanwhile, cook the pasta in plenty of boiling water according to package direction.
Drain pasta and return to pan. Stir in pesto, add spinach, and toss until spinach begins to wilt. Gently mix in roasted tomatoes, basil, tomato paste, and sundried tomatoes. Serve warm.