Like many other Americans, I grew up under the impression that most savory meals ought to be served hot. "Eat before your food gets cold!" is a line I remember hearing not only from anxious TV moms, but also from my own dad once in a while. Now that I'm all grown up and cooking for myself, the effort it must have taken my parents to get every dish hot off the stove and onto the table at the same time isn't lost on me. But the necessity of doing so is starting to be, since plenty of the foods I enjoy most taste just fine, perhaps better, when they've had a few minutes to cool down—or, alternatively, warm up. And it isn't just me. As descriptors go, "tepid" is no one's idea of appetizing, and "room-temperature" is an admittedly imprecise designation that's more often attached to ingredients in baking recipes—eggs, butter—than a suggestion for serving.…