Also called false
morel (Gyromitra esculenta), this
mushroom shows great variety in its
toxicity depending on the exact sub-species and whether we are dealing with North American or European
turban-tops. Those found in
North America are usually all poisonous, whereas some European varieties are actually quite tasty.
All turban-tops are brown with grey or beige hollow stem. Their cap looks a lot like a small maroon brain with chambered interior. In Europe, it can be found during the spring, growing close to conifers on dry, sandy areas.
The poison compound of these mushrooms is called monomethylhydrazine. If ingested, it destroys the victim's red blood cells and causes kidney failures as well as damage to the central nervous system. Symptoms usually begin between two hours and a day after ingestion and can include liver failures, vomiting, diarrhea, jaundice and finally coma after a signifucant number of red blood cells have been destroyed. Fatality rate from liver failure, should one occur, is something from 15 to 40 percent. Overall fatality rate from monomethylhydrazine is also quite high at 15 percent.
Especially with European varieties, the toxins can be removed by drying or boiling, rinsing and reboiling. This is a lengthy process but worth the effort, since turban-tops are definitely standing on the yummier end of the mushroom spectrum.
Should you be lucky enough to live in Scandinavia, where the mushrooms seem to be less poisonous than elsewhere, the proper course of action is to chop your mushrooms into small slices, then throw them into boiling hot water (1 part mushrooms, 3 parts water). Allow to boil for 5 minutes, then remove the mushrooms and give them a good rinse. Lather, rinse and repeat, obviously after you have changed the water in the pot. If you are dealing with dried mushrooms, they should be treated in the same manner, no matter whether they have been boiled before drying or not. Moreover, dried turban-tops should be allowed to soak in cold water for at least two hours before boiling.
A nice Scandinavian recipe for a turban-top stew:
1/2 l mushrooms
2 tbs butter
1/2 onion
2 tbs flour
2 dl vegetable stock
2 dl single cream
salt
pepper
some lemon juice
Prepare the mushrooms as presented above. Throw them into a frying pan with butter, allow to cook. Add flour, stock and cream, stir continuously. Let your stew cook for about half an hour. Add some cream or milk if necessary. Garnish with spices and serve forth with some new potatoes.
It should be obvious that I take no responsibility for any mishaps with mushroom poisoning. As with all possibly poisonous food items (see fugu), use common sense and preferably get someone more competent to show you what to do for the first time.
My sources:
http://nt2.advant.com/kuocgi2/morels/
http://sivut.koti.soon.fi/kytoh/sieniopas/korvasieni.htm
The Wordsworth Guide to Poisons and Antidotes
gnOsis has kindly let me know that these mushrooms are also being called beefsteak morels or brain mushrooms, and you know what? He's right! So thank you, gnOsis.