Wash and quarter the quinces and cut out the core. Peel the quinces and cut the flesh into thin strips. Heat 2 tbsp. oil and 100 ml water in a saucepan. Cover the quince strips and steam for about 15 minutes, turning occasionally.
Wash the tomatoes. Peel and finely chop the onion. Wash the thyme, dab dry, pluck the leaves from the stems. Wash the meat, dab dry and cut into strips. Prepare pasta in boiling salted water according to package instructions.
Heat 1 tablespoon of oil in a frying pan. Brown the meat in it in portions. Put all the meat back into the pan. Season with salt and pepper. Add the onion, tomatoes and thyme, except for a little for sprinkling, and fry for about 2 minutes.
Add stock, cream and quince with liquid, bring to the boil. Stir in sauce thickener and bring sauce to the boil once. Season to taste with salt, pepper and a little nutmeg. Sprinkle with remaining thyme and serve with the noodles.