Cook the tagliatelle in plenty of salted water. Clean and slice the fresh mushrooms.
Heat the oil in a pan and fry the mushrooms vigorously. Add the chopped and strained tomatoes and milk to the mushrooms. Season with salt, pepper and Italian herbs (e.g. pizza spice) and simmer for about 10 minutes. Cut the feta into cubes, add to the sauce and simmer for another 5 minutes over low heat. Finally stir in the crème fraîche, add the pasta and mix everything well.
Tip:
If you like, you can also add rocket just before serving.