Story & Photos by Roxanne Diana What do University Medical Center (UMC), a 7-foot gumball machine, and defunct Mahoney’s Drum Shop have to do with each other? Dear Reader, I won’t keep you in suspense. The answer is doughnuts, darling. Tasked with bringing brekkie one morning, I found Pinkbox Donuts nestled in the right-hand corner of Siegel’s Bagelmania, just past…