This recipe takes about 2 hours to cook. The hands-on cooking time is about 15 minutes. It makes under a pint of sauce - enough for four portions, depending on how much sauce you like with your pasta.
I am aiming to get a pretty concentrated tomato flavour, and a texture that isn't either too wet or too lumpy - it needs to stick to the pasta, after all. The texture comes from the onions and the tomato flesh; aim to chop them so the bits are all about the same size.
Chop a large onion and fry in olive oil in a medium pot until golden. Add a clove of chopped garlic, and cook for another minute or so, enough to remove the "raw" taste from the garlic. Add the chopped flesh from a tin of plum tomatoes, and some passata or puree. You can squeeze the trimmings from the tomatoes through a sieve to get extra tomato flavour; but I don't like to cook with the cores and seeds actually in the sauce, because I think it results in bitterness. Continue cooking and stirring for another 5 minutes.
Add about half a pint of water, and a pinch of sugar if you like. Season with salt and black pepper, cover and simmer slowly for at least another hour. Check it from time to time, and add a bit more water if it's drying out.
Add plenty of chopped basil. Check the seasoning, add more water as needed, and give it another few minutes. Ready! Serve with fresh egg spaghetti (or whatever type of pasta you like) and grated parmesan.