Lately a "new" ingredient has been showing up on substitution lists and on frozen yogurt bars. Once considered food fit only for health faddists, the great flavor of carob is becoming increasingly popular with everyone.

Although carob is often described as a chocolate substitute, "chocoholics" will be doomed to disappointment if they expect it to taste the same. There is tremendous variety among the different brands, some tasting more chocolate-like than others. However, carob definitely has a unique flavor and should be enjoyed for itself. In fact, some people have come to perfer it over chocolate.

Carob powder comes from the flat, leathery pods of the carob tree -- an evergreen that is native to the Mediterranean region but found all over the world, including the United States.

After the ripened and partly dried pods of certain edible variteries are harvested, they are broken into small pieces called kibbles. These are toasted and then ground into a powder, the form usually used for cooking and baking.

The pods as well as the powder are also occassionally called "St. John's Bread." This is because they were said to have sustained John the Baptist in the wilderness. In the British Isles, the pods are sometimes referred to as locust beans because of the similarities between the honey locust and carob trees.

Even though carob powder may look and taste similar to cocoa, it acutally has many advantages over it. Carob powder is lower in calories and much lower in fat. What's more, cocoa and chcolate contain caffeine and theobromine -- two stimulants that are often considered undesirable, especially in the diets of children. In addition, they contain oxalic acid which can inhibit the absorption of calcium by the body.

Carob powder can generally be substituted in equal amounts in recipes calling for plain cocoa. Most cookbooks also say that 3 tablespoons carob powder plus 2 tablespoons liquid are equivalent to one ounce (square) melted, unsweetened chocolate. Although this sometimes works out well, certain recipes require a little experimentation before an exact determination of equivalence can be made, especially since carob powders vary so much.

The following recipes -- all family favorites -- were tested using the Laurelbrook brand of (dark) carob "flour," available in many local health food stores. It is less expensive than some other popular carob powders, has a very rich taste, and stays soft when stored in an airtight container. CAROB MOUSSE (6 to 8 servings) 1/4 cup butter 1/2 cup carob powder 2 tablespoons water 1 teaspoon instant coffee granules 1/4 cup plus 2 tablespoons mild honey 2tablespoons light rum (or a compatible liqueur) 5 large eggs, separated 1/2 cup heavy cream

Place butter, carob powder, water, instant coffee granules and 1/4 cup honey in the top of a double boiler. Heat over boiling water, stirring occasionally, until very smooth. Add rum (or liqueur) and mix in. Then add lightly beaten egg yolks and continue stirring until slightly thickened. Remove from heat and cool slightly.

While carob mixture is cooling, beat egg whites with the remaining 2-tablespoons honey until shiny soft peaks form. Mix about 1/4 of the beaten whites into the carob mixture to lighten it. Then fold in the remaining whites.

Use the same bowl and beaters (it isn't necessary to clean them) to beat the heavy cream to still peaks. Fold the whipped cream into the mousse mixture so that no white streaks remain. Spoon the mousse into individual custard disches or small serving dishes. Refrigerate several hours (or overnight) until firm. Serve cold. CAROB DROP COOKIES (2 dozen large cookies) 1/2 cup butter or margarine, softened 2/3 cup sugar 1 large egg 1/2 teaspoon vanilla 1/2 cup buttermilk or sour milk 1/2 cup water 1/2 cup water 1/2 cup carob powder 1 teaspoon baking soda 1/2 teaspoon baking powder 1/4 teaspoon salt 2 cups unbleached white or whole wheat (pastry) flour Icing (optional)

Use electric mixer or food processor to cream butter and sugar. Beat in egg. Add vanilla, milk, water and carob powder and beat (or process) until well combined. Add remaining (dry) ingredients and beat until completely mixed in.

Using a tablespoon of batter per cookie, drop into rounded mounds about two inches apart on greased cookie sheets. (I use a number 40 ice cream disher to make the job neat and quick).

Bake in preheated 400-degree oven for 8 to 10 minutes, or until top of cookie springs back when lightly touched in center. Immediately remove cookies from sheets and cool on wire racks. If desired, when cookies are completely cool spread flat bottoms with your favorite icing; then put pairs of cookies together to form sandwiches. CAROB BLACK BOTTOM PIE (8 servings) Crumb Crust: 1 1/2 cups graham cracker crumbs 1/2 teaspoon each ground ginger and cinnamon 1/4 cup butter, melted FILLINGS: 1 envelope (tablespoon) unflavored gelatin 1/4 cup plus 3 tablespoons cold water 3 tablespoons butter 1 1/2 tablespoons mild honey 6 tablespoons carbot powder 2 eggs, separated 1 egg yolk 2 1/2 tablespoons cornstarch 9 tablespoons sugar, divided 2 1/2 cups hot milk of 2 1/4 cups hot water and 3/4 cups instant nonfat dry milk 2 teaspoons vanilla 1 1/2 tablespoons dark rum 1/8 teaspoon cream of tartar Carob chips as garnish (optional)

Combine crust ingredients in order listed and mix well. Firmly press into the bottom and sides of a 9 to 9 1/2 inch pie plate (or an 8 inch springform pan). Bake in a preheated 375-degree oven for 10 minutes. Cool in refrigerator while preparing fillings. (Note: Graham crackers can easily be made into crumbs in a blender or food processor).

To prepare fillings: Soften gelatin by sprinkling over 1/4 cup water in small bowl. Set aside. Melt butter in a small saucepan with remaining 3 tablespoons water and the honey. Add carob powder and stir until completely smooth. Remove from heat. Set aside.

Put the 3 egg yolks in a medium saucepan. Use a wire whisk or mixing spoon to beat in the cornstarch and 6 tablespoons of the sugar until well combined. Then slowly beat in the hot milk (or hot water and nonfat dry milk). Place over medium heat and cook, stirring constantly, until custard thickens and just begins to boil. Remove from heat. Add vanilla.

Remove 1 1/2 cups of the custard and add to the carob mixture. Stir until completely combined. Pour carob-custard into bottom of prebaked crumb crust. Place in freezer (or refrigerator) to chill well and firm up while preparing second filling.

Add softened gelatin to remaining custard and stir until completely dissolved. Stir in rum. Place rum-custard in refrigerator and cool, stirring occasionally until slightly thickened (about 1/2 hour).

Next place the 2 egg whites in a clean mixing bowl with the cream of tartar.

Beat until foamy, then gradually add the remaining 3 tablespoons sugar and beat until stiff and shiny. Stir about one-third of the beaten whites into the cooled rum-custard to lighten it. Then fold the custard into the rest of the whites, making sure that no streaks of white remain.

Spoon this mixture over the chilled carob layer, heaping it in the center if necessary. Decorate with carob chips (whole or grated), if desired. Chill in refrigerator at least 3 hours, or overnight, before servng.