ON AND off during our years in Washington, I have thought longingly of Raie au Beurre Noir. I might never have tasted raie had I known it was the unlovely dish we call skate or sting ray. But ignorance and poverty do much to make a palate sophisticated, and when I lived in Paris in the 1950s I ate a lot of this most inexpensive, delicious, meaty, unfishy of fishes in the very cheap restaurants I could afford.

I cooked skate when we lived in New York, where it is usually obtainable at Italian markets. For the most part, however, the wings (the edible part) are used as bait and, according to my research, skate appears in Washington retail fish markets "very rarely" -- if ever.

So a few weeks ago, before I went to New York for a few days, I invited friends for a skate binge for Sunday evening, the day after I was to return. On Friday morning I bought at a superior fish market in Chelsea two wings, each cut in half, 5 3/4 pounds in all, at $1.09 a pound. The next morning I packed plenty of ice cubes around the fish, put it into the super heavy plastic bag the store gave me, placed this into a heavy brown bag and that into a shopping bag.

I got onto the train with a pound of prosciutto, a pound of zampino, an Italian salami (these for my husband, not for the dinner), the skate and eight artichokes which, at 35 cents apiece (the going price was about $1), were the come-on at Lexington Avenue fruit and vegetable market I happened to pass. By the time we pulled into Union Station, I generated the aura of a third-class carriage on a Sicilian train; but although a bit of water had leaked through the plastic, the shopping bag held.

The afternoon we picked up three pounds of mussels, some cream and eggs for Billi Bi, the soup that would be the first course, and parsley for the brown butter and boiled potatoes which are traditional with skate.

The mussels I scrubbed, debearded and debarnacled that afternoon. I also minced the parsley and cooked the artichokes in advance since these would be eaten cold with a shallot, mustard and herb vinaigrette, as a combination green and salad with the skate. (It's a kindness to remove the chokes -- after cooking, pull out the center leaves in a bunch, spoon out the choke and return the leaves.) Dessert was brought by friends.

The soup I did on Sunday in two increments, following Michael Field's "All Manner of Food" (Knopf, 1970). First the mussels are cooked as for moules mariniere , but without the butter enrichment. Since the broth and only some of the mussels would be used for the soup, I saved as many half shells as left over mussels for stuffed mussels with remoulade sauce (from the same Michael Field volume). These made a glorious first course the day following the dinner.

For the skate I turned to Jane Grigson's "Fish Cookery," an invaluable Penguin volume (1975). The simple court bouillon was made earlier in the day and set aside to cool. (Simmer for half an hour a carrot and an onion sliced, about a dozen slightly crushed black pepercorns and a little salt in a quart of water with a cup or so of inexpensive dry white wine and a squeeze of lemon.)

The potatoes were put on about 35 minutes before we sat down. The soup was finished off (the egg yolk and cream enrichment already combined in a bowl) a minute before we began.

At the same time, I placed the fish in the cool court bouillon and brought it to the boil, lowered the heat so it would simmer, and 15 minutes later the cooked skate came out of the poacher. The gelatinous skin was peeled off and the firm white meat was separated from the bone and placed on a warm platter.

The black (brown, really) butter was also made according to Grigson: Cook a quarter-pound of unsalted butter until it is a deep golden color. (Watch carefully and remove from the heat at once. You want brown, not burned, butter.) Pour it over the fish. Swill out the pan with a couple of tablespoons of good wine vinegar, bubble for a minute and pour over the fish. Scatter with a tablespoon or so of small capers and chopped parsley and serve with the boiled potatoes in parsley butter.

This meal converted one fish-hating friend who nobly tasted and was won over. It also prompted my acculturated husband to raise a glass to "the chef and the schlepper."

The second part of that toast wouldn't be necessary if our own markets didn't force us to carry skate from New York. (A&B Shellfish promised to telephone, but "you know we get it maybe twice a year." Cannon's couldn't remember when they had skate last and had no idea when or whether they wold have it again. Chevy Chase Seafood never has it. Nonetheless skate does turn up in local French restaurants from time to time.)

You might want to try the same preparation with another fish, perhaps a thick-cut chunk of cod or haddock. I would use a stronger court bouillon, however, and poach the fish 10 minutes per inch of thickness after the bouillon reached a boil. The texture will not be the same, but the fish will taste good with the brown butter. Billi Bi Skate in Black Butter Boiled Potatoes in Parsley Butter cold Artichokes Vinaigrette Orange Roll with Orange Segments Billi Bi (8 servings) 5 pounds medium-sized mussels (about 6 to 7 dozen), washed, scrubbed, and beards removed 3 cups dry white wine 1 cup water 2 medium onions, peeled and cut into quarters, or 8 large shallot cloves, peeled Bouquet consisting of 6 sprigs of parsley, 2 celery tops with their leaves and a large bay leaf, tied together with string 1/2 teaspoon thyme 1 strip of lemon peel about 3 inches long and 1 inch wide 10 slightly crushed black peppercorns 5 egg yolks 1 1/2 cups heavy cream Pinch of white pepper or cayenne

Combine the wine, water, butter, onions (or shallots), the bouquet, thyme, lemon peel and peppercorns in a 6-quart heavy enamel or stainles-steel casserole with a tight cover. Bring to boil, lower heat, partially cover and simmer for about 10 minutes. (This can be made hours ahead and set aside.) To cook mussels bring the court bouillon to a turbulent boil, uncovered, and drop in the mussels. Cover the casserole tightly and boil briskly for 3 to 5 minutes, or until the mussels open.

Discard mussels that remain tightly closed. Pick out meat from shells that have opened and set aside. Reserve the shells for stuffed mussels. Line a strainer with a double thickness of cheesecloth and strain the broth into 2-quart heavy enamel or stainless-steel saucepan.

In a small bowl mix the egg yolks and cream only enough to combine them. Bring the mussel broth almost to a boil and stir 2 tablespoons of it into the cream-egg mixture. Then reverse the process and, whisking constantly, pour the mixture in a slow stream into the hot mussel broth. Now switch to a wooden spoon, reduce the heat to low and, stirring constantly, particularly around the inside creases of the pan, cook until the soup thickens ever so slightly. Do not allow to come anywhere near the boil or it will curdle. Stir in the pinch of white pepper or cayenne and taste for further seasoning. Serve hot with a few mussels thrown into each bowl, and sprinkle with a little finely chopped parsley. -- Adapted from "All Manner of Foods" STUFFED MUSSELS WITH REMOULADE SAUCE (4 to 6 servings)

Reserve about 3 dozen mussels and an equal number of half shells from the Billi Bi recipe. Chill the mussels. Fill the shells with the remoulade sauce and half submerge a mussel in each. Top, if you like, with a dill, tarragon or parsley leaf and refrigerate until ready to serve. REMOULADE SAUCE (Makes 1 cup) 1 teaspoon dry mustard 1 teaspoon lemon juice 1/2 teaspoon capers, drained and finely chopped 1 tablespoon chopped fresh dill, or 1/2 tablespoon dried tarragon 1/2 tablespoon finely chopped parsley 1/4 teaspoon chopped garlic 1 hard-cooked egg, finely chopped 1 cup freshly made mayonnaise or a good unsweetened commercial mayonnaise Salt to taste Pinch of cayenne pepper

In a deep bowl, stir the mustard and lemon juice together until the mustard is completely dissolved. Add the capers, dill or tarragon, parsley, garlic and chopped egg. When they are well combined beat in the mayonnaise.Stir in the salt and cayenne and taste for seasoning. The flavor will develop. -- Adapted from "All Manner of Foods"