In March 2012, Universal Edition Vienna announced the publication of Helder’s orchestration of Mahler’s Piano Quartet, commissioned by the Rotterdam Philharmonic Orchestra. It was premiered in May 2013 by the RPhO and conductor James Gaffigan. The Asian premiere will be held in November 2014 with the Seoul Philharmonic and Mark Wigglesworth. She was commissioned by the re:orchestra to write her first double concerto for violin and bassoon which was also premiered in May 2013.

Helder has performed with several Dutch and German orchestras and toured in Russia, the USA, Mexico and Europe. Her works are frequently performed in cities around the world.
Her concerts include a wide range of repertoire, including chamber music for voice and piano, violin and piano, cello and piano, piano trio and piano quartet.