I dont have a soup recipe, but I did try it in risotto recipe I have from an Italian pork cook book. You basically finely dice the lung, use a basic risotto recipe with meat. that is, fry the onion, garlic, maybe some celery all finely chopped with the diced lung. add a tablespoon of tomato paste and a glass of white wine, some good stock. etc etc ( I am assuming you know basic risotto technique). topped with butter and generous Parmesan. I loved it, the flavor was great, but the texture of lung is not for everyone. I'd make it again.