We're paying respects to a treat that is universally loved and has stood the test of time -- the doughnut! Alton Brown takes us on a trip to Memphis to honor the original glazed doughnut that started it all. Alex Guarnaschelli goes weak in the knees for an apple doughnut from New York City. And we can't contain our taste buds as Scott Conant shows off all the tropical flavors of a coconut cream-filled delight.