It is very important to soak the cockles in cold water for at least 2 hours, changing the water 2 or 3 times. Rinse them thoroughly.
Sweat the shallot and garlic in a pan with olive oil. Add the cockles and white wine and cook over high heat until open. Remove the cockles that have not opened (the shell surely died during transport).
Reheat the whole wheat spaghetti in lightly salted boiling water for 75 seconds and drain.
Pour the spaghetti, chopped parsley and butter into the pan with the cockles and gently mix everything together.
Arrange the spaghetti nicely on hot plates, arrange the shells on the side, pour the rest of the sauces from the pan and decorate with the lemon zest.
Cold line preparation
Prepare the cockles as explained above. It is also possible to cook them in the steamer (3 to 4 minutes at 100° C with 100 % steam). Set aside in the fridge, having removed all the closed cockles.
When cooked in the steamer, you will have to prepare the sauce separately. Sweat the shallot and garlic in olive oil, add the white wine, let the alcohol evaporate and season. Add butter to thicken the sauce and finish with the flat-leaf parsley.
Let the whole wheat spaghetti thaw according to food safety rules.
Arrange the pasta and cockles nicely in a tray, cover with some sauce and garnish with lemon zest.