Obviously, Alkan's most famous work is the enormous set of Etudes op 39.
But I think the Etudes op 35 are also well worth checking out. Apart from
no 5, "Allegro barbaro", they are not heard often enough.
There is yet another, though smaller, set of Etudes op 76, brilliantly
recorded by Hamelin on Hyperion CDA 66765. It's recorded live, and I still
can't believe my ears... There is also a wonderful transcription of the
first movement from Beethoven's Piano Concerto no 3 on that disc.