Boil pasta and prepare the vegetables: peel and dice the onion; clean the pepper and cut into 1-inch squares; slice the zucchini; trim and quarter the mushrooms; peel and crush the garlic.
Heat the oil in a deep frying pan. Add the onion and sauté until it is translucent. Add the garlic and vegetables, salt, pepper, and basil and toss to combine. Cover and cook over medium heat until the vegetables are tender.
Drain cooked pasta and add to the vegetables with half of the nuts and mix well. To serve, top with remaining nuts and grated cheese if desired.