At least an hour before, put the cockles in a bowl of fresh water. Wash other shellfish separately in several waters.
Place the mussels in a casserole dish over high heat and let them open. Remove them from the pot and put them in a bowl. Replace them in the casserole with the clams, then with the cockles and proceed each time in the same way.
Wash, dry and chop the herbs. It takes a tablespoon of each herb.
Shell the shells, put them in a large salad bowl, add the herbs and mix.
Pour the oil into a bowl, grate the lemon zest over it, then squeeze the lemon and add 2 tablespoons of juice to the bowl, salt and whisk the mixture.
Peel the tomato after having plunged it for 1 minute in boiling water then cut the flesh into cubes.
Peel the onions, cut them into strips and add to the shellfish, along with the diced tomatoes. Pour the sauce into the bowl, mix. Adjust the seasoning if necessary.
Clean and spin the lettuce leaves. Divide them among the plates. Arrange the shellfish mixture in the centre, sprinkle with ginger powder and serve.
Blanc de Chine is a name given to powdered ginger
