THE FLORIDA Keys offer some of the most beautiful skies, water and fishing in the world . . . and some of the best dining. The variety of fresh seafood -- fish, shrimp, oysters, clam, conch, blue crab, stone crab, and Florida lobster -- rivals any in the world for sweetness, flavor and texture.And my favorite place to eat it is down U.S. 1 from Key Largo (between mile markers 82 and 83), at Ziggy's Conch.

The walls in Ziggy's are painted a tired old green and decorated with indigenous fish that have been stuffed, mounted and labeled, thus providing an informative decor for the curious. Ziggy's reminds me of the Mediterranean restaruants in Spain, where the atmosphere tends to be straightforward and businesslike -- large, plate-glass windows, wooden tables and chairs, and linoleum floors. The food, however, is reminiscent of Batiste's, a restaurant in Santa Pola, Spain, that gets my vote as best seafood restaurant in the world.

Ziggy, according to a swamp-rat friend of mine who owns a restaurant in the Everglades that specializes in alligator meat, was an oldtime gambler who realized back in the 1940s that northern high-rollers would part with the bucks for excellently prepared South Florida seafood: "So he run up to Islamorada and bought himself The Conch. Next, he went over to Europe to find the best chef he could talk into returning to the primitive (in those days), 'skeeter infested Keys." The Conch was an instant success.

Andre, the chef from Europe, moved on about 10 years ago and old Ziggy finally died, but his son Alan, along with Quebec-born chef Henri Champagne, carries on the tradition. Chef Champagne's Fish California, a dish featuring broiled slices of red-brown tomatoe and cool green avocado atop a delicate fillet of dolphin (a fish with white meat not to be confused with the mammal of the same name), covered with a rich porous and light-yellow bearnaise sauce, is an example of what I mean about the Florida Keys. FISH CALIFORNIA (2 servings) Brown sauce: Veal bones Assorted vegetables Wine Tomatoe puree Bearnaise sauce:

Chef Champagne's directions are vague; if they make you nervous, use a standard bearnaise recipe. Water Egg yolks Butter Margarine Lemon juice Chopped tarragon leaves Tarragon vinegar Salt and pepper For the fish: 2 fillets of dolphin (or any fresh white fish) Worcestershire sauce 1 lemon Salt and pepper Flour 2 eggs, beaten Margarine 2 slices avocado 2 slices tomato

The brown sauce is one of Chef Champagne's secrets, but he did reveal the above ingredients. Take his cues and go to work with free-form abandon! Cook it for 13 hours.

Make the bearnaise sauce by adding a little bit of water to the egg yolks and beat over moderate heat until they begin to thicken.Remove from fire and add a mixture of half butter and half margarine, which has been stirred lightly. Blend in this mixture gently and then add lemon juice, chopped tarragon leaves, tarragon vinegar, salt and pepper.

Season the fillets with worcestershire sauce, lemon juice and salt. Roll them in flour and dip them in beaten eggs. Lightly saute the fillets in a pan with margarine (butter, the chef insists, burns). Place the sauteed fillets on the lower reck of a 350-degree oven and bake until they are flaky -- 12 to 16 minutes or so, depending on their thickness.

As the fish is baking, slice the tomato and avocado and place the slices in an 8-by-8-inch baking pan. Remove the fillets from the oven when they are done, place the pan with the tomato and avocado slices on the upper rack of the broiler and turn the oven to broil.

Place a couple teaspoons of brown sauce on the fillets and fix something to drink, which will give the tomato and avocado just the right amount of time under the broiler. Remove and place one of each on the fillets. Pour on the bearnaise. Return the fish to the broiler just long enough to brown the bearnaise -- no more than 1 minute.

Chef Champagne, to hs everlasting credit, does not believe in the obligatory salad or baked potato. The meal could begin with a chowder -- preferably conch, but fish or clam will do just fine -- and then his Fish California, served with a lovely bottle of chilled white wine, is perfect.