Busoni's Berceuse élégiaque is a deeply profound and harmonically complex work written in response to the death of his mother. It is highly distinct for its eerie, shifting tonalities and suspended, dream-like atmosphere.
Achieving the correct balance and layered textures is extremely difficult, requiring subtle control of the pedal and touch.
Comparable difficulty and character — good candidates for what to learn next.
Berceuse élégiaque, BV 252a is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 9.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Berceuse élégiaque, BV 252a lasts about 5 minutes.
Berceuse élégiaque, BV 252a is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Berceuse for Piano, BV 252 by Ferruccio Busoni, Albumblatt, BV 272 by Ferruccio Busoni, Albumblatt, BV 272a by Ferruccio Busoni — see the full similar-pieces list on this page.