Unless one is eating in a dim sum parlor, there’s a good chance that the dumplings and bao gobbled up in any given establishment have been frozen at some point in their existence. Depending on how long they’ve been in the freezer, and how well they’ve been sealed, this doesn’t generally have a deleterious effect. Few frozen pizzas are very good — even the priciest ones don’t keep pace with fresh brick oven pies — but a wide swath of