One of the amazing things about our society's addiction to nutritional advice is how long debunked notions stick around. Take the great cholesterol ban of the 1980s. Study after study has proved that dietary cholesterol intake and blood cholesterol levels aren't necessarily related, but health-conscious Americans still order scrambled egg whites and substitute margarine for butter. Not in the bistro world, where the egg yolk is recapturing its former glory. Chefs around town are serving eggs with liquid yolks atop meats, pastas, and salads, and diners are discovering that a just-punctured yolk quickly forms an unctuous, buttery sauce. Take Spur's linguine with duck-egg yolk, a golden custard that coats the noodles and sautéed mushrooms beneath it as you twirl them around your fork. Or Marination Mobile's kimchi fried rice, topped with a sunny-side-up egg that gushes out when you dip in with your chopsticks, the yolk's richness counteracting the bite of the pickled cabbage. Spaghetti carbonara, frisée salad with lardons and poached eggs, uni nigiri with raw quail egg—we crave it all.—Jonathan Kauffman Various fowl.