This takes me back to childhood holidays in Cornwall! Whilst out on a seaside walkies along the Solent I saw these winkles - or common periwinkles at low tide.
I checked with a local wildlife warden that the sea quality in this part of the Solent is excellent! Strong tides bring fresh water to the area twice a day.
So I picked a bucket of winkles from the rocks and picked some seaweed to pack with them. After cleaning thoroughly I soaked them overnight in salt water to allow them to filter out any sand or impurities.
Boil in salty water , with the seaweed, for about 10 minutes and then cool in the fridge for a couple of hours.
Fiddly work to get them out of their shells with a needle or a pin (my Grandfather was a London pawnbroker so we have some long pawnbrokers pins for the task) It is well worth the effort. Serve with vinegar and pepper on a slice of wholemeal bread. Perfect!