I was aware of these, but had never tasted them until they turned up on a dish in France a few years back. They were so beautiful in flavour and texture I ate the same the following evening. The rule of thumb now is that if morels are on the menu in any guise whatsoever I have to have it, even over scallops or fillet steak.
Unfortunately trying to get hold of fresh ones is like getting a ticket for the 100m Olympic Final. Mainly found in France and the US. Luckily though they are available dried. Although expensive, they still make any dish outstanding, as once rehydrated they can be eaten as normal without tasting like rubber.
Their main advantage is in the spongelike body they possess. Not only does this hide sauce inside the cavity, but also they suck up loads of sauce, so a mouthful just lingers on the taste buds with the robust mushroom still coming through. If you see them, treat yourself one day and follow my sauce guidelines on the Wagyu Beef/flying saucer dish. I know they will not disappoint.
They are said to have slight intoxincating symptoms when consumed with alcohol! If ever you had a good reason to blame the hangover on something else.