Cook the pasta in salted water according to the instructions on the package.
Fry the spring onions cut into rings with the chopped garlic in oil. Add the sliced mushrooms and fry until shriveled. Add the spices and fry briefly. Pour in the cream and let it boil down a little.
Mix the water, flour and a little vegetable stock. Add the roux to the pan so that the sauce thickens nicely. Bring the sauce to the boil until it becomes thick.