Choose Dutch or French on the sunny isle St. Martin

Until I rolled into the petite beach town of Grand Case one palmy afternoon, I'd always figured Manhattan's 55th Street for having the most restaurants per square block anywhere. I soon lost count on the mile-long drive through this French West Indian outpost, but an even dozen would be a fair assessment--Italian, Spanish, Creole, Vietnamese, and of course every flavor of French.

Not all of the eating spots will be there next year or even next month. Some of the French owners have a habit of closing down for the summer and reopening restaurants back home in the metropole. Others will fold as quickly as they opened, but I am guessing that the colorful one-road village, already growing accustomed to the fickle ways of Restaurant Rue, will smile through the changes.

It's no accident that the suddenly blooming port, a mere spot on the map a few years ago, would choose the shores of St. Martin to sprout a culinary thicket. Commerce knows few bounds on the island, jointly tenanted by French and Dutch. The Dutch have generally been more active developers here, but now that the French have their own pot boiling--not just in Grand Case but in Marigot, the largest town, and elsewhere on the once sleepy north side--the distinctions may begin to pale.

Sint Maarten, as the island is known on the Dutch end, still has more and bigger hotels, fine beaches, acres of tennis courts, and a capital, Philipsburg, that has become the Waikiki of the Netherlands Antilles almost overnight (though its shops are even less aesthetically assembled than those on the Kalakaua Avenue strip). St. Martin, as the French spell it, is quieter, greener, hillier. And, thanks to Grand Case and Marigot, more delectable.

Not that the national demarcation--intact since 1648--is everywhere so distinct. You pass as easily from one side to the other as you would from St. Paul to Minneapolis. There are back-to-back welcome signs at the border--''Bienvenue Partie Francaise'' and ''Welkom aan de Nederlandse Kant''--to tell you you're leaving France and entering Holland. You can use guilders and francs, but every transaction may be done in dollars as well. I didn't find a French or Dutch coin in my pocket all week.

Though Restaurant Rue will lose a beat or two in the low season that is already upon us, this is for many the choicest time of year to visit St. Martin/Sint Maarten or any other Caribbean island. From April 15 to Dec. 15, hotel rates drop anywhere from 30 to 55 percent, and the islands, less in the sway of tourists then, get back their old rhythms. Transportation becomes a more palatable proposition, too: lower fares, less crowded planes. American Airlines still comes in daily from JFK (flying time: 3 hrs., 45 min.) and Dallas-Fort Worth, and you can almost measure the relaxed post-peak atmosphere of the islands on the faces of the flight attendants.

I had the best of both worlds this last trip: comfortable lodging on the Dutch side at Oyster Pond in a 26-room hotel with the amenities of a much larger place (and a raucous red parrot guarding the open-air lobby), combined with the nearness of Grand Case, a temptation at all mealtimes.

The road from Oyster Pond to Restaurant Rue was never easy to find (even the most cultivated sense of direction can be confounded on St. Martin), but there were always willing walkers to consult, and sometimes pick up, on the roller-coaster route. I think the moment I started down the sea-front avenue in Grand Case, with its gingerbread colonial facades and long sweeping, uncrowded beach, I felt I could take a little guesthouse room and plop down for a month, tuo months, or longer. One could settle in and write the Great Caribbean Novel, between sorties to the various restaurants and cafes, walks and jogs on the mile-long beach, and late afternoon respites on the old cement pier at the heart of town.

The most substantial lodging place in town happens to be run by a family from Brooklyn. Dan Acciani, who manages the 49-room Grand Case Beach Hotel for his son and daughter-in-law, who were off the island the day I dropped by, told me that the recent profusion of restaurants is both good and bad for Grand Case.

From Mr. Acciani's assessment, other tips, and my own taste tests, I would give top rating to the venerable (for Grand Case) L'Auberge Gourmande. Sebastiano does the right stuff with northern Italian cookery, Hon Mai (also a guesthouse) with Vietnamese food, and L'Escapade with nouvelle cuisine. Chez Martine also gets high grades, both as a restaurant and as a seven-room guesthouse where in summer you can have a double room for $30 or $35.

Perhaps the place of widest renown is La Nacelle, a pretty, balustraded, pink-shuttered building that Charles Chevillot, a far-ranging restaurateur, has fashioned from the old village gendarmerie. Two can easily spend $90 for dinner. Which would mean a month of baguettes and cheese for the Great Caribbean Novelist.