Sculptor Rachel Mount cannot be labelled a conventional artist but her fanciful, witty work fabricated from sugar and cake seems to present more problems to the "but is it art?" brigade than Turner Prize winner Chris Ofili's penchant for elephant dung.

Mount says the root of her obsession with sugar might be traced back to her grandfather, who died in an accident in a large sugar refinery - a typically tongue-in-cheek, oblique response from this talented but enigmatic artist.

Mount designs, bakes and constructs edible masterworks from a small studio space in Wandsworth, South London, crammed with books, magazine cuttings and photos of movie stars. A picture of a young David Niven diving into his Los Angeles swimming pool holding a bow and arrow in the manner of Cupid, wearing trunks and a tweed deerstalker hat, is typical of Mount's offbeat, razor-sharp eye for the absurd.

Mount left school at 16 and never attended art college. Working as a waitress, she became aware of "the very dull" cakes her customers ordered for parties - "square and pink with a bit of piping on top". This inspired her to create something herself and the first cake she made was an ashtray design, which she gave to her manager as a birthday present. From that moment she became "totally devoted to my new craft".

Mount refers to herself as "a creative magpie" absorbing ideas from books, films, art and theatre. London is a "jewel box of inspiration" and she scours markets and thrift shops for movie annuals and old cookbooks that contribute to her bank of constantly evolving ideas. But she is adamant that her sculptures "must satisfy the mouth as well as seduce the eye". For commissions that are going abroad she makes a "cake" in polystyrene and then decorates it in icing sugar (these will likely become very collectable).

Although she can now list a pedigree roster of international celebrities for whom she has created unique edible art works, such as the Victoria and David Beckham (Mount made their wedding cake), Ronnie Wood and Tom Cruise, she is most enthusiastic about a "theatre of blood" sugar doll's house with trick internal trapdoors she made for a cast party for the Improbable Theatre Company. An equally elaborate cake depicts fantastical scenes of characters and show themes for the Young @ Heart Chorus, a company of pensioners from Massachusetts, which reinvents pop songs with new meaning and energy.

Not content with numerous sugary masterpieces, including a tableau featuring stacks of elegant suitcases, shoeboxes and pairs of shoes; a witty "Tarts' Card" public phone box creation with cards displaying candy messages such as "Very Strict Cake Mistress" and "Sweet Treats for Well Behaved Birthday Boys"; and an enormous multi-tiered Sound of Music Cake featuring Julie Andrews cavorting across the top for a private client in Salzburg, Mount's most ambitious aspiration was to be selected for the 2006 Summer Exhibition at the Royal Academy.

Alas her 5ft-high triptych, "Two Faced French Fancies", inspired by her father's death, which explores "the social layers of cake", was rejected. Perhaps the judges did not have the stomach for Mount's monumental and intricate piece. But she is a gifted artist whose work is full of wickedly observational wit and irony and often a dark message lurking beneath its sweetly innocent exterior.

The rejected entry caught the attention of Sotheby's chief executive Robin Woodhead, who offered her an opportunity to exhibit it and other examples of her unusual oeuvre at Sotheby's Bond Street galleries - just around the corner from the Royal Academy.