For the curry cream soup, peel and finely chop the onion and sauté in butter. Add curry and flour, stir well, fry briefly, extinguish with wine and pour soup.
Bring the soup to a boil and season with ginger, salt, pepper and grated nutmeg, mix with crème fraîche and simmer on low heat for about a quarter of an hour.
Puree the cream of curry soup with a hand blender, pass through a fine sieve and season with salt and pepper.