Cook the pasta according to the instructions on the packet. At the same time, clean the mushrooms, cut the spring onions into fine rings and the mushrooms into strips. Mash the garlic.
Sauté the garlic, mushrooms and spring onions in heated butter, pour in the white wine and stock, add the crème fraîche, bring to the boil and simmer for 2 - 3 minutes over low heat.
Season the oyster mushroom sauce with salt and pepper to taste, thicken it with a sauce thickener and add to the pasta. Garnish with parsley if desired and serve.