The cupcake craze is petering out, but the Elvis cupcake from the Oh for Sweet's Sake truck may be the epitome of everything that's good about the reinvented classroom treat. A banana cupcake is smeared with a thin layer of peanut butter, then topped with chocolate icing and sprinked with bacon. Salty, sweet, savory and a little meaty; the only thing missing is a dusting of chili powder for some heat. The Elvis cupcake is special and not available all the time, which just makes the serendipity of finding it all the more worthwhile. If chef/owner Lisa Johnson doesn't have the porcine treat, she offers plenty of other combinations to tempt the senses. $