A cockle is a type of edible saltwater clam. There are more than 200 living species of cockles and can be found all over the world. They are collected by raking them from the sands at low tide. As a word of caution consumption of raw cockles has been linked to hepatitis however, you definitely want to buy any shellfish alive! The reason for this is that dead shellfish tends to spoil very rapidly, and if you do not know how long it has been dead, it is hard to know whether or not it is safe to eat.
And so you can try them in a recipe (from here):
1/3 cup extra-virgin olive oil
6 garlic cloves, sliced
1 medium onion, minced
3-4 small dried cayenne peppers
1 cup dry white wine
1 cup water
1 1/2 pounds (750 grams) linguine
2 pounds (1 kilo) cockles (soaked in salted ice cold water for a minimum of 1 hour)
1/4 cup butter, in pieces
1 bunch flat leaf parsley, roughly chopped
*optional, but recommended* 2 tablespoons cornstarch mixed with 1/3 cup water
freshly grated parmesan cheese to taste
Get your water going for the pasta…you’ll want to salt it fairly heavily and bring to a rolling boil.
Meanwhile, begin your sauce.
Heat olive oil in a wide, medium depth soup pot.
Saute garlic first, just until beginning to turn golden, then add onions and saute until translucent and tender.
Add cayenne, wine and water and cook about 3-5 minutes over moderate heat.
By now, your pasta water might be ready, so pop the noodles in there and prepare according to package directions.
When the pasta is done, drain well and return to the pot.
Season the sauce with salt and freshly cracked black pepper, then add the cockles and cover.
Cook over moderate heat for about 5 minutes or so, until cockles have opened (discard any that haven’t opened, they’re not fit to eat).
Remove from heat, add butter and parsley and stir.
Add cornstarch slurry if using and stir some more, then reserve.
Is your pasta back in the pot? Time to pour the cockles and sauce over your pasta and stir well to combine.
Discard any empty shells you find.
Sprinkle with parmesan to taste and enjoy!