Place the dried mushrooms in a bowl and pour over enough hot water to cover. Leave to soak for 20 minutes.
Heat the oil in a large saucepan, add the onion, celery, carrot and garlic and cook over a low heat for 8 minutes, stirring occasionally, until softened. Increase the heat, stir in the mushrooms and cook for 3–4 minutes.
Strain the soaked dried mushrooms through a sieve, reserving the liquid. Add the mushrooms to the pan.
Pour over the wine, bring to the boil and cook until reduced by half. Stir in the reserved soaking liquid, tomatoes, tomato purée, vinegar and oregano, season with salt and pepper and bring to the boil.
Reduce the heat, cover and simmer for 40–50 minutes until the sauce is thick and the mushrooms are tender.
Meanwhile, cook the spaghetti in a large saucepan of lightly salted boiling water for 8–10 minutes, or according to the packet instructions, until al dente. Drain and serve immediately topped with the mushroom mixture, with vegetarian pasta cheese grated over.