Combine the onion, celery, carrot and garlic in a food processor and blend to form a coarse paste. Heat a heavy saucepan over medium heat and add ½ cup of olive oil. Fry the paste (called a battuto when raw and soffritto after cooking) for about 15 minutes, stirring regularly so that it doesn't burn. Stir in the passata and salt, cover and simmer for 45 minutes, stirring occasionally.

Cook the spaghetti in plenty of salted water until al dente (usually about 1 minute less than the packet directions). Heat a very large frying pan over medium heat and add the remaining ½ cup of olive oil. Add the cherry tomatoes and cook for just a minute, then add the cooked pasta and ladle over as much of the sauce as you like, as well as a little of the pasta water. Stir to mix well, then transfer to serving plates and top with parsley, freshly grated parmesan cheese and freshly ground black pepper. 

Also try: Adam Liaw's rum and raisin cassata.

Find more of Adam Liaw's recipes in the Good Food Favourite Recipes cookbook.