I also want to share it because this potato salad is really just an excuse to make and eat one of my favorite sauces: Sauce Gribiche. There are lots of uses for Sauce Gribiche, and I think it should be in every cook's repertoire. Sauce Gribiche is a classic French sauce—you can find it in Escoffier. It is one of the many variations of mayonnaise, which is one of the French "mother" sauces. (All classic French sauces are variations on or derivations of one of the "mother" sauces.) If you know how to make mayonnaise, you can make Sauce Gribiche. Of course, as I write this, it occurs to me that many people, maybe most, have never made or even tasted a real, freshly made mayonnaise. It is not difficult, but it does require some understanding and instruction--a future post maybe....
Sauce Gribiche differs from mayonnaise in that it uses hard cooked egg yolks, instead of raw, as its foundation. Most people, myself included, cheat and add a raw yolk—this seems to make the sauce more stable and a bit easier to make in small quantities. The sauce is augmented with some, or all, of the "fines herbes" (parsley, chives, tarragon, chervil), cornichons or gherkins, capers, shallots and the chopped hard cooked egg whites.
The first time I came across this sauce was as a cook at The American Restaurant where it was served as a garnish for a roast chicken breast (served with escarole braised with ham hocks). It is very good with chicken. It is also nice with simply prepared (blanched, braised, roasted) vegetables. You can find it in the Chez Panisse Café Cookbook as a sauce for grilled Belgian Endive . Classically, however, it is served with fish. Tartar sauce probably comes from sauce Gribiche.
I made a double batch so that I would be able to have some for dinner on Saturday. I had purchased some beautiful white-top turnips and baby green beans at the farmers' market that morning and I thought all day about just having a spread of vegetables to go with my sauce, but I saw some nice Arctic Char at the grocery store and ended up having my Gribiche with its traditional partner.
Potatoes are another great partner for the Gribiche. Frank Stitt includes cooked potato in the sauce itself. In her book The Vineyard Kitchen, Maria Helm Sinskey makes a new potato salad by dressing potatoes and a little minced celery with her version of Sauce Gribiche. I don't even think you need the celery. For my potato salad, I used all-purpose potatoes. I cooked them in their skins in boiling, salted water until they were tender. When they were cool enough to handle, I peeled them, diced them and tossed them with a little white wine vinegar while they were still warm. When they were cool, I added the Sauce Gribiche. You should add as much as you like (I think 2 to 2 1/4 pounds of potatoes is about right for one recipe of Gribiche) .
Sauce Gribiche2 hard-boiled eggs
1 egg yolk
1 T. Dijon mustard
½ t. kosher salt
¾ to 1 c. vegetable oil
Tepid water, as needed
1 to 2 T. freshly squeezed lemon juice
pinch of cayenne
1 ½ T. capers, rinsed and coarsely chopped
1 ½ T. chopped cornichons
2 T. finely minced shallots, rinsed
1 T. minced flat-leaf parsley
2 t. minced chives
1 t. minced tarragon
Pass the hard-boiled egg yolks through a fine sieve and place in a bowl with the raw egg yolk. Finely chop the hard-boiled egg white and set aside.
Add the mustard and salt to the egg yolks and whisk until smooth. If the mixture seems too stiff, add a few drops of tepid water. Begin to add the oil drop by drop while whisking steadily. When an emulsion begins to form, begin to add the oil in larger and larger amounts until all of the oil has been absorbed. If at any time the mixture becomes unmanageably stiff, add a few drops of water.
Stir in the lemon juice, along with the remaining ingredients and the chopped egg whites. Taste and correct the seasoning with salt, cayenne and lemon juice.
Makes 2 cups sauce.