WHEN A 50-seat restaurant an hour away from anywhere sells 60 pies and cakes a day, it is certain to be one of that nearly extinct species: a good country inn. Elsah, Ill., two streets wide and 250 residents strong, has such an inn -- although calling Elsah Landing Restaurant a country inn is to confer a misleadingly grand title on a bare-floorboards, soup-and-sandwich restaurant with a small pastry counter.

But these days a country inn, there being so few of them, is any place outside of the city to which people are willing to drive a long distance for lunch or dinner. And the lines in front of Elsah Landing -- the young, the bearded and the elderly, wearing everything from sweaters to business suits -- verify its long-distance draw.

A stone's throw -- literally -- from the banks of the Mississippi, Elsah Landing is a 6-year-old restaurant run by two ex-teachers, their sole qualifications having been that their friends considered them good home cooks. Ten years ago, Dorothy Lindgren followed her husband to Elsah where he teaches drama at the town's other main institution, Principia College. Tall and blond, sophisticated and urban, she and her original partner turned an old cracker-barrel general store that had evolved into a gift shop into a one-room restaurant. Without even knowing Helen Crafton, Lindgren invited her to join the enterprise, having heard Crafton was a good organizer. Within two years the restaurant had exanded and was drawing 80 percent of its business from out of town, mostly from St. Louis, 45 miles away.

The blackboard menu has become a revolving repertoire of 40 soups, 40 breads and 40 to 50 desserts, the desserts alone at least a dozen a day. Now one person does nothing but make pie crusts, and the staff of 28 full-time and part-time employes includes four full-time bakers and one soup cook. Although the restaurant is open only from 11:30 a.m. to 7:30 p.m., the baking starts at 4:30 in the morning. Lindgren and Crafton rarely have time to cook anymore, with running the restaurant and publishing the just-released "Elsah Landing Restaurant Cookbook."

The restaurant is a familiar mix of city and country. Ceiling fans and plants. A blackboard menu on the wall and jogging shoes on the waiters. Homegrown flowers on the tables and fresh mint in the spiced tea. California strawberries and local gooseberries.

The menu is seasonal and light, just soups, sandwiches, salads and those increasingly famous baked goods. The main courses are, in all candor, pretty ordinary; it is endearing, however, to have the option of ordering a half or a "baby" sandwich. Imagination is revved up in the soup department, the favorites being Beef Vegetable Barley, Grandma Smith's Clam Chowder (even with canned clams) and Canadian Cheese, but the most inventive being Asparagus Mushroom. And everything is let loose in the dessert department. Apple pie with warm cinnamon sauce is the favorite, but you'll rarely find a leftover piece of Mystery Pecan or Scintillating Lemon. In season there are Concord Grape and Cape Cod Cranberry Orange or Cranberry Raisin with Walnut Crust. Cheesecakes run to Avocado and Bavarian. And anybody who walks out without noticing the big round Linzer Cookies has perhaps missed the best part of Elsah Landing. By now the restaurant has developed something of an extended family, with customers sending in favorite recipes and one man coming every Saturday for custard pie, which the restaurant faithfully prepares especially for him.

"The Elsah Landing Restaurant Cookbook" puts it all between two covers, along with a chapter of Lindgren and Crafton's favorite home recipes for the likes of Stuffed Pork Chop Loaf and Fresh Green Beans and Jerusalem Artichokes. The book, printed in large type with each recipe set on a single page that lies flat in its spiral binding, reflects the originality and taste of the restaurant; its tie-in to a brand of canned milk and occasional reliance on canned cream of mushroom soup, however, reflect the compromises of a restaurant that has found it necessary to sometimes freeze its fresh vegetables and pies, to supplement its homemade stocks with canned.

On the other hand, nearly all of the recipes make lively use of fresh ingredients. The most difficult thing to teach, say Lindgren and Crafton, is how to make a light pie crust. But a sampling at the restaurant proves that they have managed to pass on that art. They also continue to grind their own cookie crumbs for cookie crusts, and have learned that the trick to their lemon pie is to clean all the pith off the peel. The running joke in the restaurant, as the book retells, is that when a new recipe is brought to the restaurant, "almost on cue one of the bakers will say, 'Oh, we can't make this. It's too simple! You don't have to chop, mince, dice, clarify, blend, knead and whip.' "

Whisks and choppers in hand, car at rest in the garage, even hungry Washingtonians can now know the mystery of Elsah Landing's pies. Recipes follow, and the book is available either in local stores or by sending $12.95 plus $1.75 postage and handling to "The Elsah Landing Restaurant Cookbook," P. O. Box 9138, St. Louis, Mo. 63117.

CORN CHOWDER (8 servings) 1/4 pound salt pork, blanched and finely diced 1 large onion, diced 2 large potatoes, peeled and diced 1/4 teaspoon thyme Salt and pepper, to taste 3 cups hot water 3 cups cream-style corn 2 cups evaporated milk, or 2 cups light cream Fresh parsley sprigs, for garnish

Fry blanched, diced salt pork in heavy skillet for 20 minutes, or until golden brown but not crisp. Remove salt pork from skillet and set aside on paper towels. Reserve drippings. Saute' onion in reserved drippings for 10 minutes, or until onion is translucent. Drain. Combine potatoes, thyme, salt and pepper with water in medium saucepan. Add reserved salt pork and onion. Cover and simmer over low heat for 20 minutes, or until potatoes are tender.

Add corn and milk or cream. Heat, but do not boil, stirring frequently so corn won't stick. Garnish each serving with a parsley sprig.

STUFFED PORK CHOP LOAF (Makes 3 1/2 cups stuffing) 1 thick pork chop per person

Bread Stuffing: 3/4 cup diced onion 3/4 cup diced celery 3 tablespoons butter 3 cups day-old bread crumbs 3/4 cup hot water 1 teaspoon sage 3/4 teaspoon salt 1/2 teaspoon pepper

Trim excess fat from pork chops. Rub hot skillet with fat. Brown pork chops on each side. Set aside. Saute' onion and celery in butter in skillet for 10 minutes, or until vegetables are tender. Mix saute'ed vegetables, crumbs, water, sage, salt and pepper together in medium bowl. Stand 1 of the reserved pork chops, fat edge up, in loaf pan. Place layer of stuffing against chop. Alternate chops and stuffing until loaf pan is full. Cover and bake at 325 degrees for 1 1/2 hours. Extra chops may be added. Additional stuffing may be baked in separate pan.

FRESH GREEN BEANS AND JERUSALEM ARTICHOKES (6 to 8 servings) 3 cups fresh green beans, cut into 1-inch pieces 1 cup celery, cut on slant 1/2 cup thinly sliced onion Boiling water 1 cup peeled and sliced Jerusalem artichokes 1/2 cup sour cream 1/4 cup mayonnaise 1/4 teaspoon curry powder Salt and pepper to taste Chopped fresh parsley, for garnish

Combine green beans, celery and onion with small amount of boiling water in medium saucepan. Cover and simmer for 10 minutes, or until just tender. Drain. Stir in artichokes. Turn into shallow casserole. Set aside. Mix sour cream, mayonnaise, curry powder, salt and pepper together in small bowl. Stir into reserved vegetables. May be refrigerated until ready to bake. Bake at 300 degrees, uncovered, for 15 minutes, or until heated through. Garnish with parsley.

MYSTERY PECAN PIE (Makes one 9-inch pie)

8-ounce package cream cheese, softened 1 egg 1/3 cup sugar 2 teaspoons vanilla 9-inch pie shell, unbaked 1 1/4 cups chopped pecans 3 eggs 1 cup light corn syrup 1/4 cup sugar 1 teaspoon vanilla 1/4 teaspoon salt

Cream together cream cheese, 1 egg, 1/3 cup sugar and 1 teaspoon vanilla in mixer bowl. Beat until fluffy. Spread mixture on bottom of prepared pie shell. Sprinkle pecans over cheese mixture.

Beat the 3 eggs in mixer bowl until well-mixed but not foamy. Do not overbeat. Add corn syrup, 1/4 cup sugar, remaining vanilla and salt. Mix well. Pour over pecans. Bake at 350 degrees for 40 minutes, or until nuts are lightly browned. Top will rise like a souffle' and sink as it cools. Serve warm or cold. May be frozen. Thaw at room temperature.

LINZER COOKIES (Makes ten 3-inch cookies)

This cookie is a distant relative of the Linzertorte from the city of Linz. Although it does not contain nuts, it is filled with the traditional raspberry jam. 1 cup butter 1/2 cup sugar 2 cups sifted flour 1/4 teaspoon salt Raspberry or blackberry jam

Cream butter and sugar in mixing bowl until fluffy. Add flour and salt and blend to make a smooth dough. Refrigerate for 2 hours. Roll out dough 1/4-inch thick on floured board. Cut into rounds with fluted cookie cutter. Cut out centers of 1/2 of the rounds to form rings. Place rounds and rings on cookie sheets. Bake at 375 degrees for 10 minutes, or until lightly golden. Cool. Spread rounds with raspberry or blackberry jam. Top each round with a ring.

APPLE ORANGE NUT LOAF (Makes 1 loaf) 1 cup sugar 1 egg, beaten 3 tablespoons butter, melted 1 cup applesauce 1/2 cup raisins 6 tablespoons orange juice 2 tablespoons grated orange rind 2 cups flour 2 teaspoons baking powder 1 teaspoon baking soda 3/4 teaspoon salt 3/4 cup chopped pecans

Cream sugar, egg and butter together in large mixing bowl. Beat until fluffy. Stir in applesauce, raisins, orange juice and rind. Set aside. Sift flour, baking powder, baking soda and salt together in small bowl. Stir by hand into reserved applesauce mixture until flour is just moistened. Stir in pecans. Mix well. Grease a 9-by-5-by-3-inch loaf pan. Turn batter into pan. Bake at 350 degrees for 1 hour and 15 minutes, or until toothpick inserted in center comes out clean. Cool in pan for 10 minutes. Remove from pan. Cool on rack.