The after-school rush had just ended one weekday in the spring of 2015 when the phone rang at the Vanderbilt Avenue location of Ample Hills Creamery, the Brooklyn ice cream brand famous for its whimsical and elaborate flavors. Scooper Jason Smith answered the call, expecting to tell some customer what time they closed or that, yes, they still had Nonna D’s, a brown sugar cinnamon ice cream with oatmeal cookies. But it wasn’t just any customer, it was Oprah Winfrey, the kingmaker of modern media, calling to say how much she liked the company’s Ooey Gooey Butter Cake and Salted Crack’d ...