Jean-Georges Vongerichten gives Jane Sigal a class on winter salads that tosses out almost everything she thought she knew.

Usually I spend most of my time as Jean-Georges Vongerichten's editor trying to get his attention. After all, he's got 15 restaurants to run, including the new Jean Georges in Shanghai and V Steakhouse in New York City. Yet, as I learned after cooking with him recently in the kitchen at Jean Georges in Manhattan, this maverick entrepreneur has incredible, penetrating, the-rest-of-the-world-does-not-exist focus. When he trains his eye on a project, like giving a master class in winter salads, the result is an exhausting, exhilarating, toss-out-everything-you-thought-you-knew experience.

When I arrive at 9:30 a.m., he's waiting for me with all the ingredients for the first recipe—celery root salad with scallops and caviar—already organized in tin containers on the marble counter. As I tie a white apron around my waist, he holds up a gnarly celery root to his nose, like a flower. "Here, smell this," he says. It has a strong, earthy, celery odor. "I love celery remoulade," he says. "Celery root in a mustardy mayonnaise is one of the best salads, I think." He quarters the root so he's working with manageable pieces and thickly peels each with a paring knife—not a vegetable peeler, which removes only a thin layer of skin—down to the smooth white flesh; then he juliennes each wedge with an inexpensive plastic Japanese mandoline, not a fancy stainless-steel one. "You can even use a box grater," he tells me. "I suggest you julienne the celery root ahead of time and toss it with lemon juice so it softens. Lemon also makes the celery root very white." He adds the celery shreds to a small stainless steel bowl and squeezes in lemon juice. "Just a few drops."

Next, Vongerichten deals with the scallops, which he'll thinly slice and quickly broil. They are slightly coral colored. "Sometimes they are more orange," he says, "because scallops eat bits of shrimp." Taking a closer look, he says, "You see, those guys are still moving." When he sprinkles a little fine sea salt over them, the flesh is so fresh it actually shrinks.

Vongerichten tastes the dressing for the celery root, a snappy blend of mayonnaise, mustard, lemon juice and parsley. "Can you give me some salt, Danny?" he asks Daniel Del Vecchio, his right-hand man. "A little more. I want to be careful about the salt, though, because of the caviar that goes on at the end," he says, always tasting, always wiping the rim of the plate.

We try the salad. Cool, crunchy celery root; tender, warm scallops; icy caviar that squirts a salty juice in your mouth. "The flavors hit you everywhere," he says.

As we work, the waiters are setting the tables in the dining room. Several chefs are prepping in the kitchen with us; they are absolutely silent. During our two and a half hours of making salads together, Vongerichten is not interrupted even once.

Before he plates the celery root salad, Vongerichten has already started another recipe, a version of mushrooms à la Grecque, the sweet and sour marinated vegetable dish. "I'm sweating finely chopped onions with oil and coriander seeds," Vongerichten calls over to me when I linger over the celery. He works with a sauteuse, a frying pan that has curved sides. "Because the pan is rounded, you don't burn its sides," he says. He uses a rubber spatula to stir and get into the sauteuse's corners. I remember that when we tested this recipe in the F&W kitchen, everybody complained that the coriander seeds were hard. We wanted to wrap them in cheesecloth so they could be removed from the finished dish. Why doesn't Vongerichten have this problem? "The seeds soften when you cook them," he explains. "Unless you're using old supermarket coriander." Ah.

Next he adds wine, salt, ground coriander, a bouquet garni (an herb bundle of leek greens, celery ribs, parsley sprigs and thyme) and whole mushrooms: "You want all the water in the mushrooms to come out. And it's important to cover the pot so the mushrooms cook fast." Later, Vongerichten adds golden raisins, not an ingredient in the classic recipe. "That's my little add-on," he explains. One of his signature dishes, scallops with cauliflower, capers and raisins, evolved from his mushrooms à la Grecque. "One dish leads to another."

Using a slotted spoon, he transfers the cooked mushrooms to a plate. Then he whisks tomato paste and chopped tomatoes into the cooking liquid and lets it all reduce. He pours the juices the mushrooms exude back into the pan, an ongoing project since the mushrooms keep throwing off water. In the end he adds the liquid three times.

Meanwhile, Vongerichten keeps tasting the sauce. "It's getting good," he announces, handing me a white plastic spoon. "See how the flavor changes over time? The sauce is still acidic, but properly so." The tomato sauce needs to be thick enough to coat the mushrooms, he explains, but not too dry, since the raisins are going to absorb some liquid over time.

"We're done," he says. "It's finished. The mushrooms can go back in the pan with the sauce." He spoons the mushrooms in tomato sauce into bowls, then spreads blanched cauliflower florets and scallions tossed in olive oil over the top. Finally, he scatters on small mint leaves and snipped chives. "You must have a bite of the mint along with the mushrooms," he directs. "Make sure you get some mint. That's the guy." Then he sprinkles the dish with fleur de sel, French sea salt. The coriander seeds have become pleasantly tender. "It's all about the contrast," he explains: soft mushrooms, tangy sauce, fresh cauliflower and scallions, vibrant herbs. "If there's no contrast, we don't do it."

Vongerichten pauses before starting the next dish, a crab salad with apple, endive and pecans. "I haven't used this much cream in a long time," he says. He tosses the endive, which he has simply wiped clean before slicing, with cream to keep it white and to remove bitterness, then stirs in slices of Golden Delicious apple. He doesn't add any oil. There's no need; the cream provides enough richness. "I really like the apples and endive with vinegar," Vongerichten says, adding some as he turns the bowl and stirs and tastes. Then he grinds in lots of pepper. He blends homemade cocktail sauce into the crabmeat and arranges a tower of it on the endive mixture.

The salad tastes rich, but not overly so, because the vinegar sharpens the flavor. It's slightly sweet from the apples and crab. Salt makes the ingredients pop, and pecans add a bit of crunch. "It's all about balance," Vongerichten says.

As it gets closer to noon, Vongerichten becomes more animated and talks faster, unwilling to let the lesson go. We zip through three more recipes, finishing the last ones on a stove behind the marble counter, which is now laden with napkin-lined silver trays: Lunch service is about to begin. Vongerichten finally allows himself to be distracted. He takes his first cell-phone call and he's off.