ON THE TINY Caribbean island of Grenada, there may be heated discussions about which beach is the most beautiful, but there seems to O be no dispute about who holds the title of best cook. On this 120 square miles of volcanic earth (Grenada is the most southerly of the Windward Islands), visitors requesting recipes for callaloo soup, breadfruit vichyssoise, mango mousse and avocado ice cream are invariably directed to their source, Audrey Hopkin, the acknowledged local inventor of what Grenadian restaurateurs refer to as "Continental West Indian Cookery."

Hopkin holds court in the modest and cozy Ross' Point Inn, a 12-room guesthouse located midway between St. George's, the capital of Grenada, and Grand Anse, the beach-front area which now boasts about a half-dozen luxury hotels. Ross' Point Inn looks to a visitor like the comfortable home of a large family. "It was the home of my husband's father," explained Hopkin one day recently as she relaxed on the front porch, taking a short break from dinner preparations. "About 25 years ago, when my husband and I opened the Inn," she reminisced, "there was only one other place on the island for visitors to stay. Tourism was just beginning in Grenada and there were hardly any restaurants. The logical thing to do was to start a restaurant at the Inn so we could feed our guests." Although Hopkin was busy raising a family and could hardly boil an egg at the time, she decided to take charge of the kitchen.

Not long after she took ladle in hand, Hopkin hit upon an idea that was eventually to make her Grenada's most inventive and venerated cook. "Since many of our local foods are starchy and blase'," she explained, "in the early days, most of the food prepared for the tourists was flown in. This was costly, and the food was often not exceptionally good by the time it arrived. I decided to use my imagination and see what I could do to make the local produce appeal to my guests."

Hopkin began buying and studying cookbooks ("The Joy of Cooking" is one of her favorites), always reading them with an eye toward substituting local ingredients for those called for in the recipes. "I can always tell, just by reading the recipe, if the substitution will work," she said. So, for example, she tried a recipe for spinach quiche using the island's wide-leafed, mild green called callaloo instead of spinach -- with superb results. Whenever potato was required, she tried the recipe with either tannia (a starchy tuber), breadfruit (a large, bland fruit which cannot be eaten raw) or the local yam. She makes a fine "apple" pie with christophene, the green, pear-shaped squash also known as chayote.

This gifted ability to harmonize exotic ingredients with familiar modes of preparation keeps Hopkin constantly expanding her repertoire of Continental West Indian dishes, taking daily inspiration from the marketplace, where she selects the foods for that evening's dinner and creates the menu according to what appeals to her most. The absence of a printed menu at Ross' Point gives Hopkin this creative freedom and does not seem to worry her guests in the least. "I always experiment on my guests, and no one has ever turned anything away since I've had this place," she states with the confidence known only to those rare cooks who can turn near-failures into brilliant successes every time. "Many of them stay six weeks and never get the same dish twice," she adds.

Hopkin is known throughout the Caribbean for her imaginative six-course dinners (price-fixed at $15 excluding wine). On a recent evening, the menu included a smoky tannia soup with a rich beef-stock base, curried lobster and rice dotted with raisins (the island's clawless lobster has a texture similar to crab meat), a yam souffle' redolent of local bay leaves, breaded and baked plantains and a French cashew pie. (French cashew here refers not to the nut, but to a fruit which has the faint flavor of roses.)

Although Hopkin considers her recipes family secrets and is reluctant to part with any of them, she agreed to share the following recipes, published here for the first time.

BANANA RUM MOUSSE (8 servings) 1 cup milk 1 cup light cream or half-and-half 4 egg yolks 1/2 cup sugar 1 tablespoon gelatin 1/4 cup cold water 2 cups heavy cream 2 cups pure'ed bananas (about 4 medium bananas) 1/2 cup dark rum Optional garnishes: whipped cream and cherries

In the top of a double boiler, scald the milk and light cream. In a bowl, beat the egg yolks with the sugar until the mixture is lemon colored.

Whisk the eggs into the cream and hot milk gradually and cook the mixture in the top of a double boiler until the custard is thick enough to coat the back of a spoon.

In a small bowl, dissolve the gelatin in the water and add it immediately to the hot custard. Set the mixture aside to cool somewhat.

Fold in the thick cream, pure'ed bananas and the rum. Pour the mixture into a well-buttered ring mold or a decorative serving bowl and chill overnight, or at least 6 hours, until set.

PUMPKIN SOUP (4 to 6 servings)

The West Indian pumpkin, or calabaza, comes in a variety of shapes and sizes. It has a firm, delicately flavored flesh similar to hubbard or butternut squash, both of which make excellent substitutes for this soup. 2 pounds calabaza, butternut or hubbard squash 4 cups strong chicken stock 1 large onion, finely chopped 2 medium cloves garlic, finely minced 1/4 pound corned beef, finely minced (see note)* 1/8 teaspoon freshly grated nutmeg 1/2 teaspoon brown sugar Salt and freshly ground pepper to taste

Peel the pumpkin or squash. Cut into small diced pieces, discarding any seeds.

Combine pumpkin, stock, onion, garlic, and corned beef in a large soup pot. Bring to a boil, cover, and cook over medium heat until pumpkin can be easily pierced with a fork and onions are soft, about 12 to 15 minutes.

Cool slightly and then pure'e in a blender or processor. (The soup will not be completely smooth; little flecks of beef will give it a pleasant texture.) Return to pot and add salt and pepper to taste. Serve hot.

*Note: Corned beef is suggested as a substitute for the salt (salted) beef used in many West Indian recipes. Unlike the salt pork used in this country, salt beef is more meat than fat and is difficult to purchase except in West Indian neighborhoods. Corned beef purchased in delicatessens is actually salted beef which has been boiled until it is tender and most of the salt is gone.

CALLALOO SOUFFLE (4 to 6 servings)

Callaloo is the green leaf of the dasheen (taro) plant. It is difficult to find in this country (the canned variety cannot be recommended), but swiss chard, chinese spinach or spinach make excellent substitutes. 2 tablespoons butter 2 tablespoons flour 1/2 cup milk 3 large eggs, separated 1 1/2 cups cooked callaloo, swiss chard, chinese spinach or spinach, thoroughly drained and pure'ed 1 tablespoon finely minced onion generous 1/2 cup grated gruyere 1/2 teaspoon freshly grated nutmeg Salt and freshly ground pepper to taste

In a small saucepan, melt the butter, whisk in the flour and cook, stirring, for 2 minutes without letting it brown. Immediately add the milk and cook the mixture, whisking constantly, over medium heat until it thickens, about 1 to 2 minutes. Remove from heat and cool slightly.

In a small bowl, beat the egg yolks. Whisk them into the flour mixture, working rapidly so yolks don't curdle.

Stir in the pure'ed callaloo or substitute, onion, gruyere and seasonings to taste.

Beat the egg whites to stiff peaks and fold them into the mixture. Pour the mixture into a buttered 1 1/2-quart souffle dish and bake in a 350-degree oven until set and slightly puffy, about 30 to 40 minutes.