Leave chanterelles whole or cut, depending on size. Peel onions, chop finely.
Heat butter in a saucepan, fry onions until golden brown, add paprika powder, stir, immediately deglaze with vinegar. Add chanterelles, salt, pepper, stir and steam covered for 10-12 minutes until soft.
Remove the lid and let the liquid from the mushrooms boil down a little.
Mix sour cream with flour, add to mushrooms, simmer for another 5 minutes.
Serve garnished with a blob of sour cream and chopped parsley.