THOSE OF you who own Maida Heatter's books will be pleased to learn that she is a dedicated and sincere lover of desserts. Those who don't know her work will surely be tempted by a book just published by Knopf, "Maida Heatter's Book of Great Chocolate Desserts."

It may smack of over-icing the cake to propose that the author and the subject were made for one another, but in fact they were. Heatter's two earlier books, "Great Desserts" and "great Cookies," established her as the leading teacher (in print) of the difficult art of baking. Chocolate, of course, is the most romantic and sensual of all the dessert mediums and maybe the most demanding. The home cook who heads for the bakery before a party or whenever anyone in the family requests a dessert more difficult than chocolate pudding, will revel in Heatter's ability to combine taste and technique. Her patience and clarity in explaining each recipe is almost as satisfying as the repertory of chocolate specialities she presents.

There are several dozen cakes, pastries, cookies, hot and cold desserts and drinks linked by this one special ingredient. She offers Austrian-style tortes, a dozen different brownies, an amaretto-amaretti chocolate cheesecake (a personal favorite of hers) and other creations. The book also includes nine "bonus" recipes taken from her previous books.

One reason for the confidence a reader will feel even before making a recipe from the book is that Heatter is a perfectionist. (she also, for those who are trying to associate the name, has some claim to reporting skills. Her father was the famous radio commentator Gabriel Heatter.) Also, like James Beard, her work reflects a concern for form as well as substance. She has not only worked out each recipe but made it in her home kitchen. "I like to think these recipes really are foolproof," she said during a visit to Washington last week. Another reason is her approach to the subject. "I wasn't a writer.I studied art at school and was very self-conscious and insecure about writing. But I instinctively like to teach and so I tried to think of myself as teaching students rather than writing. My husband, Ralph [Daniels], would read each recipe and tell me when he needed more detail to understand it."

There is a sense of teamwork in this couple's relationship that is reminiscent of Julia and Paul Child. He likes to tell how he said to his wife, as he began to gain weight due to his dutiful sampling of her trial recipes, "Honey, I'll be any size you want me. Just remember it's your fault." He helped set the tone of her books, too. "I told Maida," Daniels said, "that when I was a student pilot during the war, the instructors all talked over my head. 'Talk at them, I told her, not down to them or over their heads.'"

It all began during the 10 years Daniels ran a Miami Beach restaurant. His wife provided the desserts and sent over written directions for distribution to customers who requested recipes. When Craig Claiborne sampled her creations and saw the recipes, he encouraged her to do a book.

Now, at an age when many couples are settled into retirement, they are barnstorming the country promoting the chocolate book and enjoying every minute of it. Her earlier books, which were given modest exposure on publication, are still in print and selling better than ever before.

"When my first book came out," Heatter said, "there was an uproar over sugar and today there is a lot of talk about diet. But people still love desserts. They talk about the 'fabulous chocolate cake' at a restaurant. It's an attraction and you see some marvelous assortments of desserts these days."

She finds chocolate a fascinating subject and has fashioned an informative introduction out of her research. In addition to learning the complex process by which chocolate is manufactured, she recently discovered that it is a "mood-elevator," that chocolate has a chemical property, phenyletylanine , that aids people in overcoming, depression. She even includes a list of its nutritional attributes, directed, she explained, toward health food stores that don't stock chocolate.

Maida Heatter's approach to recipe testing, as described by her husband, sounds idyllic. He tells of her daily ritual of "standing at two ovens in a wet bathing suit. She checks what is baking, then dives back in the pool to swim. That's her exercise." (Exercise in not enough, however. Ater the manuscript for the chocolate book was completed, she went on a high protein diet and shed about 20 pounds "so I could wear my blue suit on the tour").

It may come as a surprise, but he first warning to novice and experienced bakers alike has nothing to do with ingredients. "First, check your oven thermometer and use it. Correct temperature is so critical and merely slamming the oven door sometimes will throw the temperature off by 50 degrees.

"I do a lot of my baking ad lib, creating things I've never seen before. But baking is more scientific and precise than stovetop cooking. I've had more than my share of disasters. I expect and anticipate them."

"I see her do something 20 different times and ask 'Why do you punish yourself?'" her husband interjected.

"I don't see it that way," Heatter responded. "To me it's exciting and so much fun that I can't quit."

Nor is she quitting as an author. A fourth book, a collection of new desserts she has devised, is in the works. It will touch on some areas she has not yet explored, she said, and a hint was forthcoming:

"I think the height of everything is a perfect apple pie," said Maida Heatter, smiling with the comfort tat comes to one who has the power to make others happy.

Two recipes from "Maida Heatter's Book of Great Chocolate Desserts" follow. CHOCOLATE OATMEAL BROWNIES (24 cookies)

These taste like soft, moist macaroons. They are chewy, nutty, not-too-sweet chocolate oatmeal bar cookies, made without flour. They are easily mixed in a saucepan (children can make them), they keep well and mail well, and are extremely popular. 3 ounces (3 squares) unsweetened chocolate 1/4 pound (1 stick) sweet butter 1/2 teaspoon salt 3/4 cup dark or light brown sugar, firmly packed 1/3 cup honey 1 teaspoon vanilla extract 1 egg, lightly beaten 2 2/3 cups quick cooking (not "instant") rolled oats 4 ounces (generous 1 cup) walnuts halves or large pieces

Adjust rack to the center of the oven and preheat oven to 425 degrees. Prepare a 9-inch square cake pan as follows: Turn the pan upside down, cut a 12-inch square of aluminum foil and center it over the inverted pan. Fold down the sides and the corners and then remove the foil and turn the pan right side up. Place the foil in the pan. In order not to tear the foil, use a pot holder or a folded towel and, pressing gently against the pot holder or towel, smooth the foil into place. Butter the bottom and the sides, using soft or melted butter and a pastry brush or crumpled wax paper. (I put a piece of butter in the lined pan an place it in the warming oven just to melt. Then I spread it with a pastry brush.) Set the prepared pan aside.

Place the chocolate and butter in a heavy 2- to 3-quart saucepan over the lowest heat. Stir occasionally until completely melted. Remove from the heat and stir in the remaining ingredients in the order listed.

The mixture will be thick. Pack it firmly and smoothly into the prepared pan.

Bake for 15 minutes.

Cool in the pan on a rack for 15 to 20 minutes. Then cover with a rack and invert, remove the pan and the foil, cover with another rack and invert again, leaving the cake right side up to cool completely.

The cake may be cut into finger-shaped bars when it is cool, or it may be chilled a bit first in the freezer or refrigerator to make the cutting easier and neater.

With a long, thin, sharp knife cut the cake into thirds. Then cut each piece the short way into four strips.

These may be placed on a serving tray and covered with plastic wrap, or they may be packed in a box with wax paper between the layers, or they may be wrapped individually in clear cellophane or wax paper. AUSTRIAN CHOCOLATE WALNUT TORTE (10 to 12 portions)

This is special! It is a huge (over 4 inches high) flourless chocolate nut sponge cake that is not too sweet and is served without icing . . . The cake itself is pure drama. 7 ounces semisweet chocolate (see Notes) 8 ounces (2 1/4 cups) walnuts 12 eggs (graded large), separated (see Notes) 1 cup sugar 1/4 teaspoon salt

Adjust rack one-third up from bottom of oven and preheat oven to 350 degrees. You will need an angel-food cake pan that meaures 10 inches across the top and 4 1/4 inches in depth. It must not be coated with Teflon. And it must be the kind that comes in two pieces, the bottom and tube being in one piece and the sides in another piece. Do not butter the pan.

Place the chocolate in the top of a small double boiler over hot water on moderate heat. Cover until the chocolate is partially melted, then uncover and stir until completely melted.

Remove the top of the double boiler and set it aside for the chocolate to cool slightly.

The nuts must be ground. This can be done in a nut grinder, a food processor or a blender. In a food processor or a blender you must be careful not to grind the nuts until they become oily -- they must stay dry. They do not have to be very finely powdered but they must be ground, not chopped. Uneven pieces, some a little larger, are okay. (In a blender do only one-third or one-half at a time. In a processor you can do them all together.) Set the prepared nuts aside.

In the small bowl of an electric mixer beat the egg yolks with 1/2 cup (reserve 1/2 cup) of the sugar at high speed for 2 minutes. (Do not beat until the mixture becomes very thick.) On low speed mix in the chocolate (which may be warm but not hot). Then gradually add about half the nuts (reserve the remaining nuts). Remove the bowl from the mixer and set it aside.

Place the egg whites in the large bowl of the electric mixer and add the salt. With clean beaters, beat until the whites barely hold a soft shape. Reduce the speed to moderate and gradually add the reserve 1/2 cup of sugar. Then, at high speed, continue to beat until the whites hold a firm shape but not until they are stiff or dry.

With a rubber spatula fold one large spoonful of the whites into the chocolate mixture. Then fold in a second large spoonful.

Now transfer the chocolate mixture to a mixing bowl that is larger than the large bowl of the electric mixer. Add about 1/3 of the remaining whites. If you have an extra-large rubber spatula use it now. Slightly fold the two mixtures together; do not be too thorough. Then add the remaining nuts and egg whites and fold them all together gently and carefully.

Turn the batter into the unbuttered 10-ounce tube pan, handling it lightly in order not to lose the air that has been beaten into it. Smooth the top.

Bake for 1 hour and 15 minutes. During baking the top of the cake will rise in a dome shape, but it will flatten almost level with the top of the pan when done.

Remove the pan from the oven.

Now the pan has to be inverted to "hang" until the cake is cool. Even if the pan has three little legs for this purpose they don't really raise the cake enough. Turn the pan (with the cake) upside down and fit the tube of the inverted pan over a narrow-necked bottle (a 5-ounce Lea & Perrins Worcestershire Sauce bottle is a perfect fit) or place it over an inverted metal funnel.

Now, to remove the cake from the pan: You will need a small sharp knife with a firm (it must be firm) blade about 6 inches long. And you must be careful. Insert the blade at the inside of the pan between the cake and the pan, inserting the blade all the way down to the bottom of the pan and pressing the blade firmly against the pan in order not to cut into or to crush the sides of the cake. With a short up-and-down motion (something like using a saw) cut all the way around the cake, remembering to keep pressing the blade against the pan constantly as you cut. Then remove the cake from the sides of the pan by pulling up on the tube and/or by placing your hands under the bottom of the pan and pushing the bottom up. And then, carefully, again pressing the blade against the pan, cut the bottom of the cake away from the pan. Now cut around the tube of the pan.

Cover the cake with a flat serving plate and invert the plate and the cake. Remove the bottom of the pan.

I serve this wonderful cake just as it is. If you want to sprinkle the top with confectioners sugar, do it, leaving the cake upside down. Or make a design with strips of wax paper, sprinkle with confectioners sugar, and then remove the strips of paper.

To serve the cake, use a serrated bread knife in order not to squash this extremely light creation.

NOTES: 1. I have used Baker's Semisweet 1-ounce squares, and Maillard's Eagle Sweet, and Tobler Tradition, and Ghirardelli Eagle Sweet. I could go on and on. The cake is always delicious. Use any semisweet chocolate.

2. If you do not have the right size eggs, you can use any size. What you want is 1 2/3 cups of egg whites and a scant 1 cup of egg yolks.

3. Because removing this cake from the pan is such a ticklish job, I have been asked, "Why don't you butter the pan?" The reason is that the cake is so light and airy that it must cling to the sides of the pan or it will flop.

4. To freeze this cake, do it before removing the cake from the pan. Just wrap it all airtight in the pan. Then thaw before removing the cake from the pan.