In the 1990s, he turned his creative energies towards the theater and developed a screenplay with Tom Schulman, screenwriter of Dead Poets Society and What About Bob?. In 1993, he joined the Lehman Engel Musical Theatre Workshop in Los Angeles, where he met Rob Meurer. As a duo, with Berton as composer, Rob as lyricist, and both as book writers, they have written three musical comedies. The first show, The Party's Over, received productions in Chicago and La Mirada. The second show, Jungle Man!, has had two hit productions at Stage One in Wichita, in 2000 and 2002. Robin Hood: The Untold Story, the team's third effort, was the hit of the ASCAP/Disney Workshop in 2001 and has been seen in Los Angeles, Chicago, and Long Beach.
In collaboration with oft-produced playwright Mark Saltzman, Averre and Meurer have written two more shows. Setup & Punch premiered in the summer of 2009 at The Blank Theater in Hollywood, and received a nomination for Best New Musical by L.A. Weekly. The show will be featured in a public staged reading on October 13, 2010 at the York Theater in New York. The trio's other show, the musical Vrooom!, is a work in progress and will have readings in New York in early 2011.