First recorded by Tommy Dorsey & His Orchestra (US #1 1937).
Other hit versions by Patti Page (US #9 1952), The Chimes (US #11 1960).
Also recorded by Eddie Vedder (2011).
From the wiki: “‘Once in a While’ was written in 1937 by Michael Edwards with lyrics by Bud Green, and was first recorded the same year by Tommy Dorsey & His Orchestra.
“One of the best-known cover recordings was made by Patti Page in 1952 (on Mercury 5867). The song was revived in doo-wop style by the Chimes in 1960, with their arrangement peaking at #11 on the Billboard Hot 100 in January 1961.