Wash basil and chop the leaves coarsely. Cut onion into small cubes. Boil up wine with onion, boil down liquid almost completely. Pour in soup, stir in cream fraiche and let the sauce simmer for 2 minutes, then set aside.
Boil spaghetti in salted water until al dente and drain.
While the pasta is cooking, pound steaks gently and season with salt and pepper. Whisk eggs with the cheese. Heat a large frying pan about 2 fingers up oil.
Dredge cutlets first in the flour, then dip it in the beaten egg-parmesan mixture.
Fry cutlets on both sides, drain and pat dry with kitchen paper.
Boil up sauce, stir in basil, salt and pepper. Puree the sauce with a hand blender.