Periwinkles can be easily found on rocks near rock pools. These are herbivores and graze on seaweeds. Both periwinkles and dog whelks have a ‘door’ (operculum) which they close to protect themselves and also to prevent the snail from drying out. Pick periwinkles sporadically and from a clean source. To cook them, I like to make a court bouillon to simmer them in – a court bouillon is a light stock made from carrot, celery, herbs, water and wine. They cook quickly, roughly 10 minutes. Once they are done, use a pin to pick off the operculum and dip them in melted butter to eat.