Cook the pasta in a large pan of rapidly boiling, salted water. Drain well. Meanwhile, cook the pumpkin in a saucepan of boiling water for 10 to 12 minutes or until just tender, then drain.
Heat the oil in a large saucepan, add the garlic and cook over a medium heat for 30 seconds. Add the tomato, prosciutto, pumpkin and penne and toss gently over a low heat for one to two minutes or until heated through.
Add the baked ricotta and basil, season with salt and cracked black pepper and serve immediately.