Iterative design is a well-known methodology that involves prototyping, testing, analyzing, and refining products or processes. Rapid prototyping and evaluation are crucial, enabling designers to quickly identify and resolve issues and iteratively improve the design. However, effective iterative design relies on tools that accelerate both prototype creation and visual evaluation. This paper aims to address this challenge by presenting a framework specifically designed to enhance the iterative design process for CBR applications. In this context, we emphasize the manual and knowledge-intensive task of defining similarity measures. Furthermore, we introduce a proof-of-concept implementation of this framework based on the CBRkit toolkit and the SimViz visualization tool. We studied the capabilities to support the iterative design of CBR applications through a case study in the prototypical cars domain.