Drain the tomatoes on a sieve, collecting the juice. Peel onion and garlic and chop finely. Clean and halve the mushrooms. Clean and wash spring onions and cut them into 1 cm thick slices.
Heat the oil in a pot. Fry the minced meat in it. Cook the pasta in plenty of boiling salted water for about 8 minutes. Add mushrooms, onion and garlic cubes to the minced meat and fry for about 3 minutes. Season with salt and pepper.
Stir in tomato paste. Add the vegetable stock and the tomato juice (from a can), allow to reduce a little. Cut the tomatoes into cubes. Chop thyme coarsely. Add tomatoes, thyme and spring onions to the sauce.
Cook for a few minutes. Drain the pasta, drain and serve with the sauce. Garnish with sprigs of thyme.