Edouard Manet's painting "Dejeuner sur l' Herbe" immortalized it. Le piquenique. The impressionist's nude lady may have evoked an extreme form of relaxation, but for the French a repas en plein air is not an occasion for popping open beers beside the station wagon tailgate. Nor is it gobbling blanket-to-blanket on the grass before an evening outdoor concert. The French ideal is an all-afternoon outing, perhaps on a quiet hill above a bubbling brook, at which the guests are offered carefully prepared pates and ripe cheeses they may gently spread over crusty french bread and wash down with fine wine.

As our picnic season shifts into high gear, who could better instruct us on the art of preparing a successful fete champetre than Washington's own chefs of France? For them le pique-nique comes but once a year: September's glorious Amicale Culinaire de Washington picnic.

A picnic is a time to relax, even for 75 chefs. With a refrigerated van and rented tables and chairs, 250 dine in the style to which they are accustomed: six bushels of hard-shelled crabs for starters, two dozen pates from the city's stellar restaurants (Maison Blanche, Lion d' Or, Bagatelle and many more), 70 pounds of poached sea bass with herbed mayonnaise, 150 pounds of top sirloin grilled on the spot, wheels of brie for a breather before hundreds of napoleons, tartes aux kiwis, fraises and framboises, evantail cookies and almond tortes.

To embellish our own picnics, several chefs have offered a bouquet of recipes from their annual event. Pierre Chambrin of Maison Blanche recommended a Chateauneuf-du-Pape or a good beaujolais as an accompanying wine. "Be sure it's French," he said.

(For picnic lovers who would like to attend this September's Amicale Culinaire picnic, $15 per adult, $7.50 per child, write Box 1912, Washington, D.C. 20036.)

Maison Blanche

TERRINE DE CANARD AUX PISTACHES

Serves at least 12 1 4 1/2 pound duck 1/2 pouond veal shank 1/2 pound pork shoulder 1/4 pound chicken livers (about 4) 1 1/2 pounds fatback* 1 diced shallot 3 tablespoons madeira 3 tablespoons port 3 tablespoons brandy 3 tablespoons dry white wine Dash grated nutmeg Pinch quatre-epices or allspice 1 1/2 bay leaves 1 tablespoon salt or to taste 1 teaspoon freshly ground pepper Pinch each of thyme, sage, chives and allspice 3 eggs 1/2 cup pistachios, shelled, blanched and peeled 1 teaspoon thyme 1 bay leaf

*Before you leave the supermarket have the butcher slice 16 8-by-4-inch thin slices of fatback as a wrapping for your terrine. Then weigh the remainder for the 1 pound needed inside.

Skin and bone the duck, cutting meat and liver into 1 1/2-inch cubes. Dice the veal, pork, liver and fatback into 1 1/2-inch cubes. Dice the shallot. Mix the madeira, port, brandy and wine. Pour over the meat and shallot with all the spices except the whole bay leaf and teaspoon of thyme. Mix well and marinate overight in the refrigerator.

Put the meat and fatback through the medium blade of the food grinder. Mix eggs and pistachio nuts into ground meat. Line a 6-cup metal mold with fatback slices, leaving a 2-inch overhang. Fill halfway with ground meat mixture, then drop the mold on the floor to get rid of any air bubbles. Fill with remaining meat and drop again on the floor. Cover the terrine with the overlying fatback, add a teaspoon of thyme and the bay leaf. Cover with tin foil, pricking air holes in the foil.

Bake at 325 degrees for 1 1/4 hours. Then remove from oven and insert a metal skewer into the terrine for a few seconds. If the skewer comes out clean and is warm to your lip, the terrine is finished, If not, return to oven another 15 minutes.

When the terrine is done, remove from the oven and let sit for 5 minutes. Remove foil. Press a weight on top of the terrine. Let sit for 1/2 hour. Remove the weight, cover and refrigerate at least two days before serving

The day of the picnic, remove the larding and decorate. Bring the terrine in a picnic basket surrounded by ice blocks. Serve sliced with french bread, cornichons and small black nicoise olives.

La Bergerie

SALADE NICOISE

Serves 8 to 10 3 Idaho potatoes, boiled and cut in 1/2-inch cubes 2 6-ounce cans white tuna in water 2 ripe tomatoes, each cut in 8 wedges 2 green peppers, cleaned and cut in 2-inch slices 1 pound green beans, trimmed and boiled 4 hard-boiled eggs, quartered lengthwise 1/4 cup black nicoise olives 1/4 cup green olives 1 2ounce can anchovies (reserve 4 fillets) 2 cucumbers, peeled, halved, seeded and sliced,

salted and drained 1/2 head romaine lettuce 2 garlic cloves 2 tablespoons red wine vinegar 1 teaspoon Dijon mustard 6 tablespoons olive oil Freshly ground pepper to taste

Bring everything to the picnic in covered individual containers. At the last minute combine in a salad bowl or compose a salad starting with potatoes in the middle, surrounding them as you wish with the other vegetables, decorating with the olives, anchovies and hard-boiled eggs.

Prepare the dressing at home: mash the garlic and 4 of the anchovies in a bowl. Whisk in the vinegar, mustard and olive oil. Add pepper to taste. Place in a bottle. At the picnic shake well and pour over the salad just before serving.

La Maree

TARTE AUX FRAISES

Makes one 10-inch tarte Crust: 1 stick unsalted butter, softened 1 egg 2 cups unbleached flour 1/2 cup sugar 1/8 cup whipping cream Almond cream: 1 stick unsalted butter 1 large egg Yolk of 1 egg 1/2 cup sugar 1/2 cup sugar 4 ounces finely ground blanched almonds 4 tablespoons flour 1 teaspoon vanilla 2 pints fresh strawberries, halved lengthwise 1/2 cup apricot or rasberry jelly (optional)

Cream the butter and the egg. Make a well in the flour; add the butter and egg mixture and the sugar. Work together with the fingers, adding cream if necessary and roll into a ball. Refrigerate at least 1 1/2 hours.

Meanwhile, prepare the almond cream. Cream the butter and eggs. Gradually add the sugar and almonds. When mixed, whip in a mixer or food processor, gradually adding the flour.

Roll dough into a circle and place in a buttered 10-inch fluted rim placed over a buttered cookie sheet. With the fingers of your left hand push up the dough and with your right push out to make the sides thicker than the bottom. Roll pin over the top of mold, trimming off excess dough. With the thumb and the index finger press the sides of the dough up about 1/8-inch beyond the mold's rim. Use a fork to decorate the top of rim and to prick the bottom. Coat the base with 1/4 of the almond cream. Bake at 350 degrees for 20 minutes or until golden. Remove, cool and take off rim.

Use a spatula to spread the remaining almond cream over bottom of crust. Just before leaving for the picnic, circle the strawberries -tops facing in -around the outside rim of the crust, continuing inward until the mold is filled. Serve as is or brush with melted apricot or raspberry jelly.

Strawberries can be replaced with kiwis, bananas, grapes, oranges, pineapple or blueberries. When bringing to picnic, place the tarte on a wooden plate or a circle of cardboard.