Cook shell pasta in a large saucepan of boiling, salted water according to packet directions. Drain.
Meanwhile, process tofu, spinach, garlic and oil in a food processor until fairly smooth. Season to taste. Stir spinach mixture through cooked pasta and cook on low heat for 2-3 minutes, until heated through.
Spoon into an 8-cup heatproof dish and scatter with grated cheese. Place under a preheated grill for 5 minutes, until cheese is melted and golden. Serve with salad.