They have been on the menus around here for a very long time; being commonly excavated by archaeologists at Aboriginal midden sites along with stone artefacts and other shell and bone. They were a favoured raw material for making fishhooks; technology that seems to have taken off in southern coastal NSW within the last 1,000 years, maybe brought by wayward Polynesians.
Although you most likely didn’t know it, turban snails (Turbo spp.) have some pedigree and are still well worth eating. If the French, Catalonians (and a few other culture-bucking foragers) can make much of a thing over common garden snails (Helix aspersa), then surely there is cause for enthusiasm for a more generous version from the sea. What’s more, while in general there is an aversion to eating invertebrates from the land we seem far happier to eat them from the sea (would you eat a locust as readily as a prawn?).
The issue common to all snail eating (except for abalone, the king of them all) is the problem of getting them out of the shell. The business of boiling them so that the meat will most easily come out toughens it enough to preclude the abalone approach of fast minimal cooking for tenderness. It is not an insurmountable problem, but it does mean that turbans are one of those harvests with some preparation time attached. Boiled for 5 minutes or so, they can be tapped out of the shell; the operculum (the spiraled shell ‘door’ often made into jewellery), guts, some of the black bits and large spiral of gonads removed. Whatever you do next, thin slicing or mincing is a good idea unless you are a particular fan of chewy. The gonads can be sometimes sweet in their own right (albeit rich and not necessarily to the liking of all) but occasionally somehow bitter (seemingly more often when they are green).
For some people it is unlikely that there will be any stages of the preparation that will look or smell great. One slightly confronting tendency is for the rather tough and rubbery flesh to actually smell a bit rubbery (car tyre rather than latex) when you are mincing it. With a bit of imagination though, there are undoubtedly innumerable good ways to enjoy turban shells. Perhaps with a bit more slow cooking than other commonly eaten molluscs but still borrowing from things like Italian Zuppa di Cozze or Vongole al Pomodoro or French or Belgian moules provencale or something. Having recently and successfully followed up a tip for tenderising abalone whereby you soak it in milk for a day, this should also work. At this end of this post by the Gourmet Forager there is recipe for congee with abalone that would also work with a turban substitution. Turban meat as one of the random entries in a bouillabaisse seems possible too. I have also had success with the mince in garlic and spice patties enjoyed with sour cream, sweet chilli sauce and a dusting of salted fish roe. My latest way has been to simmer finely minced meat in a little stock and white wine until it is nearly evaporated, then I freeze it for later use. There is also a good pattie recipe specifically for turbans here.
Probably the best thing that turbans have going for them is simply that they are an underutilised resource, abundant, free, local and easily gathered. There are some better tasting sea snails out there – like Spengler’s triton (Cabestana spengleri) and cartrut shell (Dicathais orbita) – both with a crab-like hint to them that probably comes from being carnivorous rather than algae-eaters (check out a nice recent Spemgler’s triton post here) . And of course there is the unmatched delicacy of abalone (Haliotis spp.). But these are all nowhere near as abundant (and the latter subject to some tight restrictions). The green turban (Turbo undulatus) is smaller than the Sydney turban (T. torquatus) (and occasional military turban (T. militaris)) that I gather, can be gathered in the intertidal zone (where this is legal), and may be more palatable – but I have never done the taste test. The even smaller black nerite (Nerita atramentosa) occasionally gathered by Mediterranean and Asian Sydneysiders from the intertidal (and a big component of most rocky shore Aboriginal middens) also finds favour with some, often thrown in the shell in with soups or stews to add their whole flavor and some little winkle-picked morsels.
With all the seafood molluscs, the same foraging responsibility applies; they can’t run, they can barely hide, and even though few of us are out after them it requires that we follow basic sense and leave plenty behind, keep to the legal size limit (7.5 cm as longest dimension for the large turbans), and bag limit (20 per person). Although Fisheries have some cursory rules, sea snails are essentially an unmanaged fishery and therefore need to be a user-managed one – because if it ever required Fisheries to step in, in the absence of commercial lobbying their most likely response would simply be to close it. There is a plenty that should easily be maintained, and retained for those few adventurous foragers who might care about it.