1 Heat the oil in a pan and fry the onion, garlic and chillies until the onion is soft. Add the tomatoes and season with salt. Bring to the boil and simmer without a lid for about 20 minutes.
2 Cook the spaghetti in plenty of boiling salt water until al dente.
3 Puree the tomato sauce finely. Season to taste with salt and ground black pepper, add a pinch of sugar and stir in the parsley and the basil.
4 Drain the spaghetti well, mix with the sauce and serve sprinkled with freshly grated Parmesan.