Belgian chocolate truffles, selling for $30 a pound, are about as expensive as a share of AT&T. It's less risky to buy the truffles, but if you had much money invested in the stock market this year, you probably can't afford them anyway.

In fact, you probably won't be welcoming in 1988 with beluga and blini, either. At least not with your stock broker.

We advise people who are now putting their money in piggy banks to invest in inexpensive edibles this New Year's Eve: homemade truffles, cut-rate champagne, mock caviar.

The idea is not simply to buy cheap versions of the real thing. Clever manipulation is the key: making foods that are less expensive seem just as expensive, making less look like more and using originality to compensate for costliness.

Variety and color can make ordinary foods appear glamorous. Turn an ordinary chicken with a mustard sauce into more exotic chicken with three mustards, a dish with one type of pepper into a creation with four peppers, plain pasta into tri-colored twists.

Common vegetables such as beets, broccoli or sweet potatoes can be transformed into flashy ones by pure'eing them with a little cream and stuffing them into vegetables such as large mushrooms caps, artichoke bottoms, grilled tomatoes or green peppers. Mix and match the colors, putting the broccoli in the tomatoes, the sweet potatoes into the green pepper halves and so on.

Scrap the boutique ice creams for several flavors (and colors) of sherbet, scooped into a cookie cup that has been dipped in a drugstore chocolate bar melted in a saucepan.

Revive gelatin into art deco extravagance. Tilt a fluted champagne glass in the refrigerator by wedging it between two spokes of the rack. Pour a shallow layer of gelatin and allow to harden. Add another layer in contrasting color and harden. Continue the tilted layering with two or three more flavors.

Air is cheap, so go for pouf. Yorkshire puddings, souffle's and anything with a meringue look fancy, without being pricey.

Create illusions. Make your own baby vegetables by leaving the top on a carrot and carving the adjoining flesh into a tiny carrot. Make broccoli look like asparagus by cutting it in long thin stems. Totally confuse your guests by baking a mock Ritz Cracker apple pie -- with the apples.

Have presentation overwhelm ingredients. Pipe mashed potatoes through a pastry bag, arrange steamed vegetables in a hollowed-out cabbage, softly scramble a couple of eggs with cheese and cream and serve in egg shells.

Stretch expensive ingredients. Buy one lobster for six guests instead of one for each. Use the meat to garnish an inexpensive fish and the shells to make a shellfish stock, to turn into a soup or sauce. The stock can be prepared with the help of shrimp shells (the shrimp having been used to make shrimp toast or shrimp custard stuffed into avocados), and turned into a shellfish bisque, which can be eaten into the new year. To create the aura of lobsters without the expense, simply serve your fish dishes on a lobster-motif serving platter, with a lobster-shaped potholder or while wearing a lobster-decorated tie or undershorts (yes, they sell them.)

Flavor your own beverages. Pure'e a couple of pears with sugar to taste and a touch of lemon to keep them light, thin with a little water if necessary and pour into vodka or champagne. Make your own flavored coffee by simply adding a teaspoon of cardamom or nutmeg to the beans or the ground coffee.

Flavor your own nuts. Coat almonds with honey or with sesame oil and worcestershire sauce and bake at 185 degrees for a couple of hours, turning every 15 minutes or so. Or, flavor your own butter by blending one pound of it with a cup of chutney or apricot preserves in a food processor. Spread on tiny toast points or triangular pieces of black bread.

If you can't make food taste extraordinary, make it at least sound that way. Restaurants do it all the time, by describing a dish's ingredients, geographic origin or preparation method in sometimes excruciating detail. (Free-Swimming Nantucket Cod Gently Glazed with Our Own Oyster Cracker Crumbs, Served with Cornichon Mayonnaise. Translation: Fried fish with tartar sauce.)

Make up menu cards for your guests, or describe the dishes in a French accent as they are being served.

If all else fails, try some of these:

Caviar Eggplant caviar might not fool your guests, so let them eat mushrooms. Arrange the mushroom caviar in a white serving bowl and surround with toasted pita, black bread or toast triangles. Top with diced red pepper and/or olives to simulate real caviar. Call the dish Gribnaia Ikra ("mushroom caviar" in Russian) and it'll disappear as fast as a Zil limousine.

MUSHROOM CAVIAR (6 servings)

FOR THE MUSHROOMS:

1 cup water

1/2 cup oil, preferably olive

1/3 cup vinegar

3 cloves garlic, peeled and cut into slivers

3 bay leaves

4 whole cloves

4 black peppercorns

1/2 teaspoon salt

2 teaspoons sugar

1 pound mushrooms

FOR THE CAVIAR:

2 tablespoons olive oil

1 medium onion, finely chopped

1 clove garlic, crushed

Salt and freshly ground pepper to taste

Diced olives and red bell pepper for garnish

To prepare the mushrooms, place all ingredients except for the mushrooms in a saucepan and bring to a boil for about 5 minutes. Add mushrooms and boil for 2 minutes. Refrigerate overnight in an airtight container.

Remove mushrooms from refrigerator, drain marinade and dice. Heat olive oil in a skillet, add onion and saute' until transparent. Add mushrooms and saute' for about 10 minutes. Toss with garlic, salt and pepper. Serve topped with diced olives and red pepper and with toasted pita bread on the side.

Cheese Get it wholesale. Potomac Butter & Egg at 220 E St. SW, sells about 50 imported and 50 domestic types of cheese at about 30 percent less than regular retail prices. On the low end of the scale are mild cheddar, colby, monterey jack with jalapenåo peppers and muenster for $2.05 a pound (wheels are 3 pounds); on the high end, saga blue for $5.10 a pound (wheels are also 3 pounds). As for the ubiquitous brie, a one-kilo wheel (about 2.2 pounds) sells for $9.35.

Or, if you want to make mock boursin, try this easy herbed cheese recipe:

HERBED CHEESE ROLLED IN CRACKED PEPPER (Makes 2/3 cup)

1 small clove garlic, minced

1/4 cup butter, softened

3 ounces cream cheese, softened

2 teaspoons tarragon white wine vinegar

2 teaspoons minced fresh parsley

Coarsely ground black pepper or minced chives

With an electric mixer, blender or food processor, whip together garlic, butter, cream cheese and white wine vinegar. Stir in parsley by hand. Refrigerate at least 1 hour.

Form into a cylinder and roll in cracked black pepper or minced chives. Serve with crackers.

From "The Joy of Cocktails & Hors D'Oeuvres," by Bev Bennett & Kim Upton (Barron's, $13.95) Champagne Fancy up an inexpensive champagne by cutting it with fruit juice, dropping a colored sugar cube into it in a fluted glass, or making a Black Velvet, which is equal parts champagne and stout. Alternately, use champagne in the following punch recipe, which stretches three bottles of bubbly to 24 people.

CHAMPAGNE PUNCH (24 servings)

1 1/3 cups lemon juice

2/3 cup superfine sugar

1 1/2 quarts cranberry juice

3 1.5-liter bottles champagne

2-liter bottle ginger ale

1 cup brandy (optional)

Stir lemon juice and sugar together in a large kettle (not aluminum) until sugar dissolves. You may need to heat gently to dissolve sugar; do not boil; cool to room temperature. Mix in cranberry juice. To serve, place a large block of ice or decorative ice ring in a large punch bowl; add fruit juice mixture, champagne, ginger ale and brandy, if desired. Mix gently.

From "The New Doubleday Cookbook," by Jean Anderson and Elaine Hanna (Doubleday & Co., $16.95) Chocolate Truffles These creamy-smooth homemade truffles are just as decadent at a fraction of the cost of store-bought truffles.

CHOCOLATE TRUFFLES (Makes 50 truffles)

1/2 cup heavy cream or cre`me frai~che

10 1/2 ounces semisweet chocolate, broken into pieces

2 tablespoons orange-flavored liqueur

FOR THE COATING:

7 ounces milk chocolate

2 teaspoon cooking oil

FOR DECORATION:

1/3 cup confectioners' sugar or cocoa

To make the truffle cream, place the cre`me frai~che or heavy cream in a saucepan and bring to a boil, stirring constantly. Then remove from the heat and immediately add the chocolate. Cover the saucepan and leave for 5 minutes to allow the chocolate to melt. After the time is up, stir the chocolate with a wooden spoon or spatula to make a smooth cream; then pour the mixture into a mixing bowl and stir in the liqueur little by little. Leave the truffle cream to cool in the refrigerator for 30 minutes, removing it from the refrigerator so it will not cool too much. It should be room temperature (68 to 77 degrees) when shaped.

To make the truffles, line a baking sheet with nonstick parchment paper (stick the corners down with a little of the truffle cream). Spoon the cooled truffle cream into a pastry bag fitted with a 5/8-inch nozzle, and squeeze it out in long lines on the parchment paper. Place the baking sheet in the refrigerator for 40 minutes to 1 hour to harden the chocolate; then remove from the refrigerator and cut the lines of chocolate into pieces 1 1/4 inches long. Place in refrigerator while preparing the chocolate coating.

To prepare chocolate coating, break chocolate into pieces and place in a bowl over water that has just been brought to a boil and removed from the heat. Water should not touch the bottom of the bowl. Add oil to the chocolate, cover and let melt for 2 minutes. Stir; if not melted, let sit longer and stir again. Be careful not to let even a drop of water get into the chocolate or it will harden.

When ready to dip the truffles, have the melted chocolate coating in its bowl and the confectioners' sugar or cocoa in another shallow dish or soup bowl.

Remove the pieces of truffle cream only 10 at a time from the refrigerator. Dip each in the melted chocolate coating, then lift out and place in the confectioners' sugar or cocoa, using a fork. Set aside, each in a paper case if desired. When all the truffles have been coated, refrigerate them to harden.

To store: The truffles will keep one week in a tightly sealed container in the refrigerator, although it is best to add to the box a little extra confectioners' sugar or cocoa if keeping them for any length of time. Remove them from the refrigerator not more than a half hour before serving.

Notes: For firmer truffles, increase the amount of chocolate in the truffle cream, or reduce it for softer truffles.

Foie Gras There may not be any substitute for the rich, silken liver of a duck or goose, but Julia Child's chicken liver mousse comes at least a little close.

MOUSSE DE FOIES DE VOLAILLE (Makes about 2 cups)

1 pound or about 2 cups chicken livers

2 tablespoons minced shallots or scallions

2 tablespoons butter

1/3 cup madeira or cognac

1/4 cup whipping cream

1/2 teaspoon salt

1/8 teaspoon allspice

1/8 teaspoon pepper

Pinch of thyme

1/2 cup melted butter

Salt and pepper to taste

Look the livers over and remove any greenish or blackish spots. Cut the livers into 1/2-inch pieces. Saute' with the shallots or scallions in hot butter for 2 to 3 minutes, until the livers are just stiffened, but still rosy inside. Scrape into the blender jar.

Pour the wine or cognac into the saute' pan and boil it down rapidly until it has reduced to 3 tablespoons. Scrape it into the blender jar.

Add the cream and seasonings to the blender jar. Cover and blend at top speed for several seconds until the liver is a smooth paste.

Then add the melted butter and blend several seconds more. Force the mixture through the sieve and taste carefully for seasoning. Pack into the bowl or jar, cover with waxed paper, and chill for 2 to 3 hours.

From "Mastering the Art of French Cooking," by Julia Child, Louisette Bertholle and Simone Beck (Alfred Knopf, $22.50) Smoked Salmon Using only a quarter pound of smoked salmon for 12 servings, this spongy, slightly sweet omelet roll filled with a creamy salmon spread makes an unusual hors d'ouevre. Pre-cut the roll and serve on dark-colored plates with any of the options in the champagne section (above).

SOUFFLEED OMELET ROLL WITH SMOKED SALMON CREAM (Makes 12 slices)

Olive oil

9 tablespoons flour

4 tablespoons butter

1 1/4 cups milk, heated to lukewarm

Salt to taste

2 teaspoons superfine sugar

Pinch of nutmeg

4 eggs, separated

FOR THE FILLING:

1/4 pound smoked salmon

8 ounces cream cheese, softened

2 tablespoons lemon juice

Freshly ground pepper

1/2 cup whipping cream

Chopped chives

Line a 15 1/2-by-10 1/2-inch jelly-roll pan with foil; brush the foil with olive oil and dust it with 1 tablespoon of the flour, shaking out the excess.

To make the roll, first melt the butter in a small saucepan. Add 4 tablespoons of the flour and cook, stirring over low heat to blend thoroughly. Gradually stir in the hot milk and cook, stirring constantly until the sauce thickens -- about 2 minutes. Bring to a boil and simmer, stirring, for 3 to 4 minutes. Pour the sauce into a bowl. Beat in a pinch of salt, the sugar and a pinch of nutmeg. Beat the egg yolks lightly. Beating constantly, pour the yolks into the sauce in a thin stream. Cool to lukewarm.

Beat the egg whites with a pinch of salt until stiff but not dry. Fold one quarter of the whites into the lukewarm sauce. Sift in 2 tablespoons of flour, followed by a third of the remaining whites. Repeat with the remaining flour and egg whites. Pour the mixture into the prepared pan; level the top with a spatula.

Bake for 5 minutes at 400 degrees; reduce the oven temperature to 300 degrees and bake for 50 to 55 minutes, or until the sponge is golden brown and springy. Turn the sponge out onto a damp cloth lined with waxed paper. Remove the foil and trim any crusty edges. Starting at one narrow end, roll the sponge loosely with the cloth and waxed paper. Cool.

To make the filling, blend the smoked salmon, softened cream cheese and lemon juice together in a blender or food processor until cream cheese is light orange. Season to taste with pepper. Whip the whipping cream until light and fluffy; fold it into the cream-cheese mixture. Chill the mixture until firm.

Unroll the baked sponge; sprinkle it with chopped chives; spread with the filling and roll it up like a jelly roll. Refrigerate any extra filling. Serve cut into 12 slices, each about 3/4 inch thick.

Adapted from "Snacks & Sandwiches," by the Editors of Time-Life Books (Time-Life Books)