Olivier Messiaen
Messiaen wrote a lot of organ music which he performed himself.  One very popular work is called Transports de joie (Outburst of joy).  It is one of four pieces called L'Ascension (The Ascension).  A much longer work, consisting of nine movements, is the La Nativité du Seigneur (The Birth of our Lord).  The last movement of this piece is a toccata called Dieu parmi nous (God among us).  It has become a favourite piece for organists to play at recitals or after Christmas carol services.