Today, on the 40th anniversary of V-E Day, President Reagan addresses the European Parliament in the impressive circular assembly chamber, called the Hemicycle, of the Palais de l'Europe, the headquarters of the Council of Europe in Strasbourg, France. Meanwhile, Mrs. Reagan dines on Alsatian specialties at La Maison des Tanneurs, a charming restaurant there decorated with antiques befitting its setting in a house built in 1572.

Unlike many of the region's other restaurants, which have surrendered to nouvelle cuisine, La Maison des Tanneurs adheres to a strictly traditional Alsatian menu, for which it is noted in the Michelin Guide. Because of its strategic location in the heart of Europe, Strasbourg has belonged since the Middle Ages now to France, now to Germany, so Alsatian cooking, like the Alsatian dialect, is a unique blend of the cultural heritage of both countries.

Meals begin with foie gras, Strasbourg's claim to culinary fame, or quiche lorraine or onion tart. They continue with fish fillets in riesling sauce and coq au riesling, the Alsatian version of coq au vin prepared with the local dry, fruity white wine considered the "triumph" of Alsatian vineyards.

And while in Alsace, the sauerkraut capital of France, visitors rarely pass up a taste of the choucroute garnie a l'alsacienne, the local sauerkraut-and-pork specialty that combines German ingredients with French culinary know-how. La Maison des Tanneurs is fondly called "la maison de la choucroute" because Strasbourg natives consider its version the best in town.

This easy to prepare but impressive dish consists of Strasbourg sausages, liver dumplings, ham and smoked goose, all steamed with sauerkraut flavored with juniper berries, garlic and cloves and moistened with the aristocratic riesling wine. Sometimes, as at La Maison des Tanneurs, choucroute is cooked with cremant d'Alsace for greater finesse. This light and elegant sparkling wine, made from the finest Alsatian pinot blanc grapes in the champagne winemaking method, was awarded the rank of Appellation d'Origine Contro le'ein 1976. With a glass of the same wine, a bowl of plain boiled potatoes, a pot of spicy mustard and good country bread, choucroute seems what the natives call it, the "monument of Alsace gastronomy."

Typical Alsatian desserts served at La Maison des Tanneurs are fruit tarts and vacherin glace' a l'alsacienne, which Mrs. Reagan may try as she sips another regional specialty, eau de vie of framboise or mirabelle or other fruit, in the bright dining room with its low wood ceiling hung with wrought-iron grapevine-shaped chandeliers and green paneled walls decorated with copper food molds. As she looks past the copper pots filled with flowers and fruit that line the many windows out to the square below, Mrs. Reagan will be treated to a show of folklore dancing.

La Maison des Tanneurs is located on the Rue du Bain-aux-Plantes, one the most interesting streets of La Petite France, the quaint quarter that was home to the tanners in the Middle Ages. Like the other 16th-century buildings in this area along the river Ill, the restaurant boasts a well preserved half-timbered facade, a gabled roof and overlapping multistory attics with dormers where hides once were hung to dry.

Mrs. Reagan is scheduled to arrive at the restaurant after a launch excursion on the old shipping canals through the picturesque sections of the old customs house district, the covered bridges district, the false ramparts moat area and past the Palace of Europe.

It is a tour planned to whet her appetite for the hearty fare served at La Maison des Tanneurs and cooked today in her honor. Following are recipes of Alsatian specialties similar to those served at La Maison des Tanneurs: CHOUCROUTE GARNIE A L'ALSACIENNE (Sauerkraut, Smoked Pork and Sausages Alsatian Style) (6 servings)

2 pounds sauerkraut

1/2 pound bacon

2 cloves garlic, chopped

5 juniper berries

Freshly ground black pepper to taste

1 bay leaf

2 onions

4 cloves

Dry white wine

6 smoked pork chops

1 pound kielbasa, pricked with a fork

3 knockwurst

6 frankfurters

12 boiled potatoes

3 tablespoons chopped parsley

Mustard for serving

Rinse sauerkraut under cold running water. Drain and rinse under hot water. Squeeze to remove as much liquid as possible. Line the bottom and sides of a large heatproof casserole or dutch oven with bacon. Combine sauerkraut and garlic and place in the casserole over the bacon. Add juniper berries, pepper, bay leaf and onions stuck with cloves. Add wine to cover. Arrange smoked pork chops and kielbasa sausage on top. Cover and simmer 1 3/4 hours, adding more wine if needed. Add knockwurst and frankfurthers and cook 15 minutes longer. To serve, place sauerkraut on a large heated serving platter and arrange meats around the sides. Garnish with boiled potatoes sprinkled with parsley and pass the mustard. ALSATIAN ONION PIE

(6 to 8 servings)

FOR THE FILLING:

6 slices bacon

1 tablespoon butter

6 large onions, thinly sliced

Salt and pepper to taste

1 tablespoon flour

1 cup whipping cream

4 eggs

1/8 teaspoon ground nutmeg

FOR THE PIE CRUST:

1 1/2 cups flour

1/4 cup butter plus extra for pie plate

1/4 cup shortening

1/2 cup cold water

Fry bacon in a skillet until crisp. Drain on paper towels and crumble. Discard bacon fat and add butter to pan. Melt butter and add onions and bacon. Cook over low heat 15 minutes or until onions are soft. Season with salt and pepper. Remove from heat and sprinkle with flour. Add cream and mix well. Add eggs, one at a time, blending well after each addition.

To make the dough, combine flour, butter and shortening. Add water gradually until dough holds its shape. Divide dough in half. Roll out one half to fit a greased 9-inch pie plate. Line pie plate with dough and pour in filling. Sprinkle with nutmeg. Roll out remaining dough and place on top. Pinch edges together to seal tightly. Bake in a 400-degree oven for 35 to 40 minutes or until top is brown.