How to Make It
In a small bowl, combine the lemon juice and shallot and allow them to sit for 10 minutes. Whisk in the olive oil, salt and pepper. Adjust the lemon juice, salt and pepper to taste. Set aside 1/4 cup of each of the dill, chervil, tarragon and parsley leaves. Finely chop the remaining herbs and toss them with the chives and celery leaves.
Place about a quarter of the lettuce leaves, slightly overlapping, on a large platter, and drizzle a few tablespoons of the dressing over them. Evenly scatter a quarter of the chopped herbs, a quarter of the whole herb leaves, a handful of pulled croutons and a sprinkling of the fleur de sel over the lettuce. Pile a second layer of lettuce leaves over the first, and continue layering in the same manner until you have used all the lettuce, dressing, herbs, and croutons, finishing with a sprinkle of herbs and fleur de sel. Squeeze a little more lemon juice over the top and several grindings of pepper, as well. Garnish with a few more croutons and serve.