to convert (something inferior) into something of higher worth.
We have all had a donuts. In Dallas there is a donut shop in virtually every shopping center and I think I have tried them all. Most are mundane, with a few notable exceptions: Of course, there is Shipley's chocolate filled donut and Krispy Kreme's glazed chocolate frosted. Both are in the EMC Hall of Chocolate Fame.
I tried the Oreo and the YinYang (original/chocolate)Twist. They are definitely of "higher worth". Other great donuts, like Dark Chocolate Fudge, Butterfinger and Smores, were sold out when I got there (just before closing), so I expect a return trip VERY soon!
Run there, if you are close!