The bread pudding ($4.25) at Gugenheim's (1708 Post Oak Blvd., 622-2773) is something to behold. Served in a plain white bowl, it soars above a mantle of cream like Everest breaking through a ring of cloud. Pure joy. Its effect on me is Everest-like as well: I find myself gasping for air and fighting blackouts. People come from all over to eat this bread pudding, my waitress told me. A slight exaggeration, it turned out. One couple travels from Austin, and another from The Woodlands. But I do understand their passion. Spongy with all that rich cream, it has not only the mandatory raisins, but lots of apple as well. Quite, quite scrumptious!