* Vinaigrette of Hazelnut oil is prepared with 1 part vinegar to 4 parts oil, mustard, salt and pepper to taste.) Boil the crayfish tails and cool. Place spinach, endive, and blanched beans in a large bowl. Add tomato, shallots, chervil, and tarragon. Add crayfish tails and sprinkle with hazelnut oil, salt and pepper. Mix well and set aside.