Clean, wash and halve the zucchini, cut lengthwise into thin slices and cut these into thin strips. Clean the mushrooms, possibly wash them briefly and cut them in half or quarters depending on size. Peel and halve the onion and slice or cut it into thin strips.
Cook the spaghetti in 3-4 l boiling salted water (1 teaspoon salt per litre) according to the instructions on the packet. Heat oil in a large frying pan. Fry the mushrooms for 5-6 minutes. After about 3 minutes fry oyster mushrooms and onion. Deglaze with vinegar and simmer for 1-2 minutes until the vinegar has evaporated. Add sour cream, bring to the boil and simmer for about 5 minutes. Add zucchini about 2 minutes before the end of cooking time. Season to taste with salt and pepper.
Wash parsley, shake dry, pluck off leaves and cut into strips. Drain the spaghetti, let it drain and put it back into the pot. Add mushroom sauce and cranberries, mix everything. Briefly fold in parsley and arrange everything.