Dave Becker’s Needham restaurant, Sweet Basil, quickly developed a loyal following when he opened in 2000. Even now, he can’t change things up without hearing from customers. “A lot of the dishes that were on the menu within the first few years kind of became like a pantheon for the people that went there all the time, so like I still can’t even take things off the menu or change the colors in the bathroom without people getting angry,” he says, and laughs. “They treat me kind of like I’m the night watchman until they come back again, which I don’t care. I’m into that.” When he wrote his first cookbook four years ago, with photography by his longtime girlfriend, Nina Gallant, “Thrown Out of an Italian Kitchen: Recipes From Sweet Basil,” he tried to appease the crowds by including his most popular dishes. This time around, Becker and Gallant focus on the restaurant’s one-pot dishes in “Stewed: A Collection of Soups, Braises, and Stews From Sweet Basil,” out this month.