Here are three wonderful songs for Voice and Piano of which two of them are also composed for Voice and Orchestra by Kahn (the arrangement of the third for Pianoquintetett and Voice I have done myself since I've been asked for)
(I beg you pardon that I don't have any better Voice than the one of my PC however imperfect this solution may be, at least it allows me to explore this wonderful music for the very first time and perhaps may inspire other more giftet singers and their pianist (or conductors) to try to perform this wonderful music.)
Let me start with the:
Preludium op.31,1 "Singe, o singe dich Seele". on a late romantic poem by Christian Morgenstern, who was a personal friend of Robert Kahn.
Both the Pianoversion aswell as the orchestraversion are originally by Kahn.