This is a fungus of climates warmer than the British, and has long been collected in southern Europe, where it is found in association with the sea-hollies or Eryngium species – hence its name. I would love to report that I had found it while wandering around the coast of Portugal, but in fact I found it on a bleak grey afternoon in Leamington Spa, where I spotted its great bulbous stipes amongst a medley of exotic fungi in a grocer’s basket.
It is really good news that the delectable King Pleurotus can be grown commercially and has now reached these shores, because I would rate it higher than any other commercially growable species and at least on a level with Boletus edulis. In fact it can be grown on most of the substrates that will support its inferior cousin, Pleurotus ostreatus, and these include toilet paper. But I do get the impression that the flavour of a mushroom can be influenced by its substrate, so I would favour pulverised sea-holly, or failing that, alder sawdust (see Growing Gourmet and Medicinal (sic) Mushrooms by Paul Stamets, Ten Speed Press, 2000).