MARDI GRAS came early this year in Fox Hill West, the Potomac development -- Jan. 12, to be exact. On that evening Barrie and David Friedman gave their second annual fete in honor of the party of parties. By all reports the 50 guests left happy and very well fed.

Celebrations continue. The annual bash sponsored by the Louisiana Delegation here will be held at the Capital Hilton Saturday and the big day -- Fat Tuesday, the final party before Lent begins -- is the 19th. The Friedmanss will be there in New Orleans watching the parade, dancing and , of course, eating.

Like so many love stories, it all began on their first date, in 1968 when they were graduate students at Florida State University. Obviously smitten, David found himself talking to Barrie of the glories of Mardi gras in his home town. A wedding, three years and seven-ninths of a child later, they reached New Orleans for the festivities.

Since then, they have devoted considerable energy and time to eating well and to entertaining. Last year they decided to do a theme party based on Mardi gras. As David Friedman was serving at the time as chairman of fund-raising for the Green Acres School, the next logical step was to turn it into a benefit. Soon after a notice went up, the party was oversubscribed.

This year there was one hitch. Barrie had gone to work in her husband's office, so time was scarce. But she felt doing the party a second time would prove far easier than the inaugural effort. In addition, she could call on some cooking, there was her brother-in-law, DR. A. J. Friedman, a fervid New Orleans booster who is doing a Navy tour at Bethesda, and his wife, Devie. To rearrange the house, Barrie called on several armchair athletes who came to watch the bowl games on New Year's Day. On the night of the party there was help from David's office and the Friedman children, Jonathan, Francine and Matthew (ages 8 to 5), were drafted to pass out hors d'oeuvres and do other chores.

But good help is only one of the three rules that Barrie Friedman feels are the underpinning of a successful, do-it-yourself large party. The other two are to "plan every aspect of the party, leaving nothing to chance" and to "do as much as you can before your guests arrive."

Part of the planning, she insists, is selecting a theme, be it Mardi gras or a corned beef and cabbage meal for St. Patrick's Day. "It's so easy to do a party when you have a focus," she said last week over some wonderfully strong French Market coffee from New Orleans. "Even within the family, if I do a Chinese dinner, I will bring out special plates and serve almond cookies and tea at the end. It turns the meal into an event. The kids like it.

"For a group of 50, we decided to have some people upstairs and some in the downstairs playroom. I wanted to use the dining room for gumbo and then for the main course. But you can't keep changing a table in the middle of a party, so I put the wine in the library and the desserts on their own table in the living room. We rearranged the furniture, hung posters and decorated until the house was purple, green and gold, (the Mardi gras colors). All this was done by the time I started into high gear on the cooking because I don't want any distractions when I'm doing the food. If you are called away or lose concentration, you can ruin something. Also, there's a psychological effect. The kids were throwing beads and doubloons and listening to jazz. I was in a Mardi gras mood long before the party started."

New Orleans theme parties have something going for them besides their festive air. Most of the Creole and Cajun-inspired recipes of the region are well suited to being prepared in quantity and in advance. Some even improve on reheating.

There ar a few tricks, such as mastering the flour and oil roux that is the basis of many soups and stews, and using some "authentic" ingredients.

Barrie Friedman relies on only a handful of these pruducts: Zatarain's crab boil (liquid or dry) and Creolestyle mustard, Trappy's gumbo fillet, French Market coffee, cane syrup and Tabasco sauce. She buys all of them at local stores such as the Chevy Chase Market, the French Market and the Georgetown Wine and Food Co. Crawfish, if used, have to be flown in. Large shrimp are provided by her father, a New Jersey food broker, and the Friedmans cannot resist importing McKenzie's beautiful handmade patty shells from New Orleans. Croustades made from white bread can be substituted for the latter, however.

For this year's party, Barrie Friedman had three hors d'oeuvres passed, served a gumbo course, three main dishes and a selection of eight small pastries with New Orleans-style coffee (flavored with chicory). There were six gallons of wine and plenty of mint iced tea. All the desserts, including the traditional King Cake, were made a head and frozen. She prefers an arrangement of small desserts because "they can go on the side of a saucer with the coffee and can be eaten in a bite or two."

The traditional red beans were made ahead and the gumbo was prepared up to the point where the seafood is added. "A true gumbo is an eight-hour production from start to finish," she explaned, "but you can stop it at several points." She never adds file powder until serving time, however.

One trick she employs is to make the roux in an oven rather than stir it constantly atop the stove.For a 50 servings ings of gumbo, she combines 8 cups of all-purpose flour and 4 cups of cooking oil in a heavy (enameled cast iron) pot or Dutch oven and places it on the center shelf of a 400-degree oven. She bakes the roux for 1 to 1 1/2 hours, stirring every 10 or 15 minutes, until it has reached a deep chocolate brown and gives off an the unforgettable nutty small that is a hallmark of the true gumbos. She reports that she has successfully frozen the roux once prepared.

The week of the party, Barrie purchased avocados on Tuesday so they could ripen properly. Thursday night the remoulade sauce was prepared and mixed with shrimp so they could absorb flavor. On Friday the jambalaya was prepared, as were the crabmeat rounds. Saturday morning, frozen indgredients were brought out to thaw, patty shells were stuffed with an oyster mixture and platters were arranged. Her sister-in-law arrived with miniature muffalettos (a regional variation on the hero or hoagy) stuffed into small dinner rolls.

Her battle strategy set and the field prepared, Barrie Friedman said she had the pleasure of "feeling like a guest at my own party. I just checked into the kitchen every 15 minutes or so to see if everything was on schedule."

Should anyone be tempted to groan at such organization, the Friedman Method isn't quite flawless. "I still haven't mastered cooking rice for 50 people," she said. "Some of it stuck together, but no one seemed to mind."

Some of her suggestions for wouldbe party-givers:

For a dinner, as opposed to a cocktail party, be sure you have enough chairs so everyone can sit down. Rent or borrow them if necessary (along with plates and eating utensils) and arrange them in small groups through the house.

For a buffet, move all chairs out of the dining room and use it only for serving.

Consider food combinations and beverages carefully. Don't try to do too much of either. Serve food or different colors and textures but try to choose ones that don't require a knife, can be prepared in advance and are easy to serve. Make sure you have enough oven and burner space to heat all the foods and that last minute cooking times and temperatures don't conflict. If using chafing dishes (which also can be rented), check the burners beneath the dishes well before the party.

Allow more time than usual for large-scale preparation. Do not multiply recipes by several times. Seasoning and cooking times change with quantity. Make two double batches instead of trying to quadruple a recipe.

A pastry arrangement for dessert looks appetizing and offers a variety of taste. Think small. Any pie can be a tiny tart. Cakes can be baked in mini-muffin cups or on a flat pan, and cut into small squares. When in doubt, dust with powdered sugar. It covers a multitude of sins.

Professional help is expensive, but you may be able to hire students or draft your children for some chores. Accept any offer of help but be sure the jobs are clearly defined and that there is a timetable of what has to be done when and by whom. Then go enjoy your company. That's what parties are for! OYSTER PATTIES Makes 48 hors d'oeuvres or 4 main servings) 2 dozen oysters 3/4 cup oyster liquid 4 tablespoon butter 5 tablespoon flour 1/2 cup chopped onion 1/2 cup chopped celery leaves 4 patty shells (large) 1/2 cup chopped green onions 1/2 cup chopped parsely 2 cloves garlic, minced 1/2 teaspoon salt 1/4 teaspoon black pepper 1/4 teaspoon hot pepper sauce

Drain oysters, reserving liquid. Melt butter; stir in flour, making a dark brown roux. Lower heat; stir in the onions and celery. Cook until soft, about 10 to 15 minutes, stirring often. Lower heat to simmer; then stir in oyster liquid to blend. Add parsely, garlic and seasonings; simmer 10 minutes. Next add oysters and bring to a boil, then simmer 10 minutes. If sauce is not thick enough, continue to simmer to desired thickness. Heat patty shells in oven. Fill with above mixture just before seving. Fills 4 large patty shells with extra juice. Oysters may be cut for smaller cocktail-size patties which will fill 48 small patties, or substitute crustades. CRUSTADES 24 slices fresh, thin-sliced white bread 2 tablespoons soft butter

Coat the insides of 24 muffin tins with softened butter. Cut bread into 3-inch rounds and place them into the tins, molding the bread to form a cup in the tin. Bake for about 10 minutes at 400 degrees.Crustades may be frozen for future use. NEW ORLEANS CRABMEAT ROUNDS 1 pound crabmeat 2 green onions, minced 1 cup grated cheddar cheese 6 tablespoons mayonnaise 50 toast rounds (French bread with crust preferred)

Mix crabmeat, onions, cheese and mayonnaise very gently. Correct seasoning. Put heaping teaspoon of mixture on each toast round; place in 450-degree oven for 8 minutes. Watch carefully. SEAFOOD GUMBO 1 recipe roux (see below)) 2 large onions, finely chopped 2 large garlic cloves, finely chopped 1 medium bell pepper, finely chopped 1 pint fresh oysters 2 pounds peeled shrimp 2 to 3 crabs in pieces, discard back shell Salt 3 cups dry white wine 3 cups water 2 teaspoons hot pepper sauce 2 tablespoon Worcestershire sauce 1/2 box frozen okra, discard ends and slice Gumbo file

Make the roux below. Add chopped onions, garlic and bell pepper. Keep stirring so that mixture will not burn. Add equal parts wine and water. This mixture should have a thicker consistency than a soup, add additional water if necessary to reach proper consistency. Add hot pepper sauce and Worcestershire sauce. Bring to a boil. Add raw shrimp, oysters and sliced okra. Cook over a slow fire for about 2 hours. Boil crabs. Discard back shell and break into pieces, bodies and claws. Add the bodies and claws to the gumbo and serve with rice and file powder.

Note: File is a powder made from the leaves of the sassafras tree. The file serves to thicken the gumbo after it has been cooked. Put the file in the gumbo at the time you serve the gumbo. Leftovers may be frozen. Roux 1 1/2 cups sifted flour 1 small can tomato sauce 1 small can tomato paste 3/4 cup oil (olive preferred)

Cover the bottom of a heavy 5-or 6-quart pot with olive oil. Heat the olive oil well over a slow fire and add the flour. Cook the flour slowly, stirring continuously. The flour should be very dark brown but not burned. The secret to a good roux is to cook it slowly to remove the floury taste and to insure a uniform coloring. Add one small can of tomato paste, stirring this continuously until the roux has reached the color of the flour before the paste was added. Then add a small can of tomato sauce and repeat the process. this should take 1 hour or more. The mixture should be dark brown. RED BEANS AND RICE 1 pound red kidney beans Ham bone with meat when available or 1/2 pound ham plus smoked sausage (not kielbasa) 8 to 10 cups water 1 onion chopped 2 cloves garlic chopped 1/2 small green pepper chopped 2 tablespoon celery chopped 2 tablespoon parsley chopped 1 large bay leaf Salt to taste

Rinse and sort beans. Soak beans for several hours and discard water. Add hambone and fresh water (mixed with dry red wine if desired) until beans are covered. Render ham and sausage in skillet. Remove meat and reserve. Saute in fat in skillet, onion, garlic, pepper, parsley and celery. Add these with meat, bay leaf, salt and pepper to beans. Boil gently, stirring occasionally for about 2 hours or until soft. Add water while cooking if necessary. Add hot pepper sauce to taste (optional). Serve over rice. CHICKEN JAMBALAYA 1/4 cup cooking oil 1 chicken, cut into serving pieces 2 medium onions, chopped 6 green onions, chopped 2 green peppers, chopped 2 cloves garlic, minced 1/2 pound cooked ham, cubed 1/2 pound sausage, sliced 1 can (16 ounces) tomatoes or equivalent of fresh tomatoes peeled and seeded 1 can (6 ounces) tomato paste 1 teaspoon salt 2 bay leaves 1/2 teaspoon powdered thyme 2 sprigs parsley, chopped 4 cups cooked rice 1/2 to 1 teaspoon hot pepper sauce 1/2 cup water if necessary

Heat oil in skillet, brown chicken pieces on all sides, remove from pan. Add onions, green onions, green pepper and garlic to skillet and cook until the onions are transparent. Remove. Add sauage and ham. Saute until sauage is cooked through. Add tomato pieces, tomato paste, reserved vegetables and all seasonings. Stir in cooked rice gradually until thoroughly mixed, adding water if mixture is too dry.

Place rice mixture in baking dish and top with the browned chicken pieces. Cover, so that mixture will not dry out. Bake 1 hour at 350 degrees.

Jambalaya is usually served with the chicken stirred into the rice and cooked in a large kettle on the top of the stove, but it is more attractive for serving when the chicken is on top. AUNT DEVIE'S SPECIAL CREOLE PRALINES (Makes 1 3/4 pounds) 3 cups packed light-brown sugar 1 cup heavy cream 1/4 cup margarine or butter 2 tablespoon light corn syrup 1/4 teaspoon salt 1 teaspoon vanilla 1 1/2 cups pecan halves, toasted lightly

In a large, heavy saucepan mix sugar, cream, butter, corn syrup and salt. Bring to a boil over medium heat, stirring to dissolve sugar. Cook syrup and stir occasionally to a "soft ball" stage. Remove from heat, let stand 5 minutes. Stir in vanilla and pecans. Beat with spoon until mixture begins to thicken and lose its gloss. Drop by 1/2 tablespoon onto waxed paper to form patties about 2 inches in diameter. Wrap in plastic and store in airtight container. PECAN TARTS (Makes 2 dozen) 3/4 cup firmly packed light brown sugar 1 tablespoon butter or margarine, melted 1 egg, slightly beaten 1 teaspoon vanilla extract 2/3 cup chopped pecans Cream cheese shells (recipe below) Sweetened whipped cream (optional)

Combine sugar, butter, egg, vanilla and pecans, mixing well; spoon 1 teaspoon filling into each pastry shell, pressing shell in center if necessary. t

Bake the tarts at 350 degrees for 15 to 17 minutes. Cream Cheese Shells 1 package (3 ounces) cream cheese, softened 1/2 cup butter or margarine, softened 1 cup all-purpose flour

Combine cream cheese and butter; cream until smooth. Add flour, mixing well. Refrigerate dough 1 hour; then shape into 24 balls. Place each ball into a greased miniature muffin tin, shaping into a shell. Bake at 350 degrees for 15 minutes before filling.