Until the day I stumbled on a dissenting voice, a plea on behalf of the overcooked; unsurprisingly, it came from an Italian, Marcella Hazan. Her cookbooks are full of recipes for vegetables rendered soft and yielding in slow-simmering water—olive oil baths, the cooking liquid itself as delectable as a broth. Nothing complements roast chicken like her braised artichokes and leeks, olive green and silky; her braised celery stalks reveal a luxuriousness you wouldn't expect from celery. I was certain there must be scientific corroboration for what Hazan and generations of cooks before her knew based on experience at the stove. I phoned Dr. Keith Harris, assistant professor of food science at North Carolina State University, to see if he could shed light on that elusive vegetal sweetness that comes with long cooking. "It's true that when vegetables, especially cruciferous vegetables, are cooked, the damage to the plant's tissue brings about reactions between compounds that are usually kept separate," he said—hence the sulfuric aroma. But, he emphasized, if you continue to cook these foods, "at a certain point the aroma will dissipate, and you'll end up with the flavor compounds left in the plant, including its sugars—especially if it's cooked and served in a way that the sugars aren't poured out with the cooking water."