At both branches of Buvette, Jody Williams's restaurants in New York City and Paris, sumptuous small plates are served throughout the day from 8 a.m. until 2 a.m. in cramped spaces that ooze French-country charm. In the morning, croissants and steamed eggs are on the menu, and at night, pâtés and French-leaning tapas appear.

Whatever the time of day, Williams has considered how to make every morsel served feel extra-special. "We cook with a certain sense of purity and emphasize whole, natural foods. I put a lot of thought into what's coming into my restaurant and what's going into my pots and pans," she explains. "Certainly soupe au pistou," says Williams of the classic vegetable soup with pesto, "is flush with health and nutrients."

Like the dishes served at Buvette, and the recipes that fill the pages of her newly released cookbook, the soup reveals much about the chef's ability to make rustic, soulful dishes lusty and authentic. A slew of vegetables, including warm-weather newcomers like squash and green beans, cook down with creamy dried beans and nothing more than water until everything turns velvety and lush. At the table, a bright pesto gets stirred into bowls and, if the diner chooses, extra Parmesan.

"When we use the word wholesome in the book, those recipes deal with real food," she explains. "For me there is no such thing as too much butter or fat -- if you are eating balanced meals, you don't need to think about that."

While worrying about precise nutritional breakdowns doesn't keep Williams awake at night, almost every other details pertaining to eating well does. "This soup needs to cook for a long time. Just when you think it's all done, you need to cook it even more until it's like a porridge," she says. "On the hottest day in summer, this is beautiful served just barely warm. All across the book -- whether we're talking about wine or coffee or making a special lemonade -- the point is to embellish your life at the table. It's indulgent."

You can speed up the cooking by substituting two 15-ounce cans of beans for the dried beans. Simply rinse the beans under cold running water and drain them. Add them to the soup once the vegetables are tender and let the whole mixture cook for 15 minutes before serving.

Place the soaked beans, all of the vegetables, the chile flakes, and 2 teaspoons of salt into a large soup pot and cover with cold water. Add 2 additional cups of water.

Bring the mixture to a boil, lower the heat, and allow it to simmer until the beans are tender, about 1 hour, adding more water as the soup cooks if it gets too dry or too thick at any point. Season the soup to taste with additional salt and chile flakes, if necessary.

Meanwhile, place the basil leaves in a mortar and use a pestle to crush them with 2 teaspoons of salt. Work in the Parmigiano-Reggiano and the olive oil to make a coarse paste. Alternatively, you can pulse the basil, salt and Parmigiano-Reggiano together in a food processor and stream in the olive oil to make the paste. Either way, season the pistou with additional salt, if necessary, and set it aside. A thin layer of olive oil poured on top will prevent the pistou from browning.

Serve the soup hot, topped with a generous drizzle of olive oil, a big spoonful of the pistou and a handful of grated Parmigiano-Reggiano.

Kitty Greenwald is a Brooklyn-based food writer and recipe developer. She eats a lot for work and pleasure. Her column Slow Food Fast appears in the Wall Street Journal.

Recipe excerpted from the book BUVETTE by Jody Williams.  © 2014 by Jody Williams.  Reprinted by permission of Grand Central Publishing.  All rights reserved.