Build a show-stopper for dessert

Croquembouche - that towering pyramid of filled cream puffs drizzled with a delicate net of caramelized sugar - makes a spectacular centerpiece and dessert. It's made with a simple and classic French dough - the choum or poufm paste. Chou (pronounced ''shoe'') is French for cabbage - something the little pastries are thought to resemble. Croquembouche literally means to ''crunch in the mouth.''

Traditionally it is shaped like a Christmas tree, but there is no reason it has to be. Also, the pyramid shape can present structural problems. It sometimes comes out crooked and has been know to collapse - especially in damp or warm weather, or if made too far ahead.

If you insist on the pyramidal shape, metal cones are available with complete directions to facilitate their construction.

To eliminate the architectural risk, try one in the shape of a wreath. It has the added advantage of not looking out of date when presented on, say, a New Year's Eve table. Decorated with a red bow, it's a show-stopper.

Most any cookbook has a simple hand method of making a chou paste, but if you have a food processor available, try this method. It whips the whole thing up in seconds.

The Cream-Puff filling below is from Jean Anderson's, ''New Processor Cooking'' (William Morrow & Co., $17.50). If it seems too complicated, simply fill the puffs with your favorite filling. Food Processor Chou Paste 1 cup water 1/4 teaspoon salt 1/4 pound butter (unsalted is best) 1 cup sifted flour 4 eggs

Put first 3 ingredients in a heavy saucepan and bring to a boil.

Add flour to processor bowl, with metal chopping blade in place. Start motor and slowly add hot mixture to flour. Continue processing until mixture is thick and glistening - about 40 seconds.

Add eggs 1 at a time and process for 10 seconds after addition of each egg. Scrape down work bowl and process again for a second or two.

With a 1/2-inch plain tip in place, fill large pastry bag with chou paste. Tube one inch high round mounds on ungreased cookie sheet, leaving a 2-inch space between each puff.

Bake in 400 degree F. preheated oven for 20 to 25 minutes, or until puffs are nicely browned and sound hollow when tapped. Remove immediately to cooling rack. Makes about 4 1/2 dozen.

You may not need all puffs for the wreath. Any leftovers may be frozen for future use if they are not filled. A ''dry run'' on a platter the size of the wreath you want may be useful. Cream Puff Filling 2/3 cup sugar 6 tablespoons flour 1 cup heavy cream 1 cup light cream 5 eggs 1 teaspoon vanilla

Place half the sugar and all the flour in food processor fitted with metal chopping blade. Blend 5 seconds. With motor running, slowly add heavy cream. When cream has been incorporated, stop motor and scrape mixture into medium-size heavy saucepan, and stir in light cream. Set aside.

Add remaining sugar, eggs, and vanilla to processor. Pulse or snap motor on and off about twice to beat lightly. Let mix stand a few moments.

Meanwhile, set saucepan containing flour and cream mixture over moderate heat and cook, stirring constantly, until sauce mixture is quite thick, about 3 minutes, or until no starch taste remains. Quickly spoon half of hot sauce into egg, sugar, and vanilla mixture and pulse processor on and off about 3 times. Scrape down bowl with a plastic spatula. Add remaining hot sauce and combine as before.

Pour mixture back into saucepan and whisk lightly. If you are afraid of mixture curdling over direct heat, pour into top of a double boiler and set over simmering, not boiling, water.

Set saucepan over lowest heat (moderate heat if using double boiler) and cook , stirring constantly, until quite thick and no raw egg taste remains - about 2 to 3 minutes over direct heat, 8 minutes or more in double boiler. Remove thickened filling from heat and cool to room temperature, whisking often to prevent a ''skin'' from forming on surface. Cover cooled filling and chill until quite firm.

With small plain tip in place, fill large pastry bag with mixture. Make a small hole in bottom of each puff and pipe in mixture. Wreath may be assembled several hours before serving, but should not be kept too long as it can become soggy. Caramelized Sugar 2 cups sugar 1/2 cup water

Pour sugar in a small, heavy saucepan and heat slowly over very low heat, stirring constantly, until sugar is melted and light brown in color, about 10 minutes.

Remove sugar syrup from heat and add 1/2 cup water, heated to almost boiling, very slowly and carefully to avoid spattering.

Return to low heat and continue to stir for another 8 minutes or so until syrup is a rich golden brown. Be careful not to let syrup burn, and remember that it will continue to cook to some extent, off the stove, from heat of heavy pan. Assembling of wreath

Grease a heavy round glass dish with shortening. Dish should be the size you plan to make the wreath.

Working quickly, dip the bottom of each puff pastry in caramelized sugar and place in concentric circles on glass dish to form bottom of wreath. As you finish the first layer, add another layer or two until all puffs are used. Carefully drizzle some of remaining caramelized sugar over finished wreath to hold it together. When cool, decorate with bow or holly.