A long-time favourite among musical theatre buffs, American songwriter William Finn is best known to the general public, insofar as he is known to them at all, for his sprightly, sardonic show March of the Falsettos (1981), which is regularly performed on the Edinburgh Festival Fringe by American college groups.

Any fears that Finn’s ain’t what he used to be are dispelled in this beguiling, if messy to look at, cabaret conceived by Rob Ruggiero and directed by Andrew MacBean. How many singers does it take to sing “Four Jews in a Room Bitching”? Six, with pianist Matthew Brind supplying the rhythmic, eloquent, busy accompaniments on piano.

Finn is a full-on composer, whose bountiful musical invention nonetheless belies a fairly modest output. His latest Off-Broadway show is The 25th Annual Putnam County Spelling Bee (2004), here represented by a dictionary song in which Nietzsche is rhymed with (and related to, apparently) Christina Ricci, while the programme also carries enticing tasters of A New Brain (1998) and Elegies, A Song Cycle (2003).

He can vamp like Kander and Ebb, rhapsodise like Sondheim, knock ’em dead like Jerry Herman, but it’s sometimes hard to pin down a defining character in the songs beyond their obvious craftsmanship and lyric intensity. Something in them suggests that the author might be both homosexual and Jewish, with a solid mean streak (“Poor, Unsuccessful and Fat” is one of nastiest funny songs ever), but then a beautiful number like “I Went Fishing With My Dad” comes spinning at you from left field.

That song is charmingly done by Ian H Watkins, formerly of the pop group Steps, and another surprise highlight is the meshing of “I’d Rather Be Sailing” with “Set Those Sails” from Finn’s first musical, In Trousers (1979) by Simon Thomas – soon to be seen in Marguerite – and Louise Dearman.

Dearman is a big blonde with a big voice. She has considerable competition from the ever-delightful Frances Ruffelle, who discharges “Stupid Things I Won’t Do” (written for Elaine Stritch) while sitting on a chap’s lap in the front row, and the ever-impeccable Sally Ann Triplett who finds a double meaning in “Change” similar to that mined by Jeanine Tesori and Tony Kushner in Caroline, or Change.

Gareth Snook completes the sextet, hitting high notes in some catchy key changes and generally setting the gay, liberated, tumultuous mood in “Hitchhiking Across America.” Make Me a Song is simply designed by Ben M Rogers with a small ramp, an evocative slide show – views of Manhattan and leafy vistas – and a few bar stools.

But the costumes and hairstyles could do with a make-over. Everyone looks so glum and grungy. Who wants day clothes? We want day-glo ... and love and romance; let’s grace the music in dance, not pants.

- Michael Coveney