Francis Mallmann turns the heat up high—really high. Argentina's star chef explains the secrets of his art to Peter Kaminsky

Francis Mallmann's position as Latin America's pre-eminent chef depends on more than mere cooking. Most of it can be summed up in one word: style. Everything Mallmann does speaks of elegance as easy as a Fred Astaire soft shoe. Tall, fair-haired, with ice-blue eyes, and often sporting a Sinatra-ish fedora, he cuts a figure that is flamboyant yet somehow never showy. Mallmann is all about the perfect gesture, from the banquettes in his Uruguayan restaurant—knockoffs of a seventeenth-century church pew that caught his eye in Bergman's Smiles of a Summer Night—to the handwritten poetry that covers the walls of his dining rooms. So yes, he is a cook, but his sense of taste extends far beyond food on a plate.

Take, for example, a Francis Mallmann fête champêtre in 2002 on the occasion of the announcement of a joint venture between Eric de Rothschild, proprietor of Château Lafite Rothschild, and Nicolas Catena, who is to Argentina's Mendoza wine region what Robert Mondavi is to the Napa Valley.

A group of 30 guests caravanned from town, past terraced vineyards and into the cool uplands. An avenue of poplars—leaves aflame with autumn gold—brought us to a stream. Two good-looking wine stewards in double-breasted blue tunics and white aprons offered Catena's best chardonnay, poured from a half-dozen bottles that lay cooling in the shady brook.

With glasses filled, we strolled back down the poplar promenade. Every hundred yards or so, another pair of smart-looking wine bearers awaited with a refill. As we passed a small farm cottage, a gaucho put on a lariat-twirling exhibition that Baron de Rothschild tried gamely, if inexpertly, to emulate.

We arrived at a clearing surrounded by chestnut trees. There, Mallmann had set up his signature cooking device, an infernillo (literally "little hell"). It consisted of two enormous black iron griddles, and sandwiched between them was a 20-pound salmon encrusted in 40 pounds of coarse salt. Underneath the bottom griddle and on top of the upper one, intense wood fires put out blast furnace levels of heat. Mallmann muscled the fish from the fire, rapped the crust with a mallet, and pulled away chunks of salt. A cloud of briny steam rose from the salmon. He made the operation look as easy as serving a piece of buttered toast, and, mirabile dictu, his white shirt remained unblemished by either fish or salt. In the manner of an archaeologist cleaning dirt from a recently unearthed relic, he brushed aside any stray grains of salt from the skin of the salmon. Meanwhile, he took some skin-on roasted potatoes and flattened them to produce what he calls "smashed potatoes." He covered one side of each squashed potato with tapenade and placed it on the grill to created an olive crust whose aroma infused the potato. He served the fish alongside the potatoes, lightly bathing the salmon in a dressing of olive oil, oregano, lemon juice, and garlic. As promised, the salmon was perfectly delicate.