Designing products and services to meet the specific requirements of children with Autism Spectrum Disorder (ASD) can be difficult due to their wide ranging and individual needs. Participatory Design (PD) is a design method that could be used to better meet these needs, by giving this population an opportunity to directly contribute to software designed for their use. Researchers have begun to involve children with ASD in the design process, but there is not yet a design method specifically adapted to support the potential difficulties this group may experience during PD sessions. This paper presents a new design method, IDEAS, which attempts to fulfill this need. The development of this method is described along with an initial pilot undertaken to determine the feasibility of using this method with an ASD population. The results indicate that the majority of children with ASD were able to produce a successful final design using this method, and have the potential to be involved in PD sessions as part of a design team.