1 Cook the pasta in plenty of boiling, salted water until al dente then drain.
2 Put into a large salad bowl and leave to cool to room temperature. Wash and slice the celery. Peel the onion and cut into wedges. Wash and halve the tomatoes.
3 Add the celery, olives, onions, walnuts and tomatoes to the pasta. Add 4 tbsp olive oil, salt, plenty of pepper and the balsamic vinegar and mix well.
4 Check the seasoning and add more salt and vinegar if necessary. Spoon on to plates, scatter generously with Parmesan shavings and serve.