Waltz Op 39 No 15 (in A flat major) composed by Johannes Brahms, performed by Paul Cantrell

Cantrell calls Brahms' Waltz Op 39 No 15 (in A flat major) a "masterpiece of sophisticated simplicity". It is indeed refined, elegant, and simple.

https://innig.net/music/recordings/ith_brahms-39-15.mp3