This paper describes the design principles and implementation of a novel approach for a K--12 teacher professional development (PD) program. The approach integrates training focused on development of model eliciting activities (MEAs) within authentic engineering design tasks, collaborative 3D model design and fabrication, and inspirational site visits with access to active engineers to enhance understanding of current issues faced by NASA aerospace researchers. Throughout the training, participants collaborated with program staff including engineering, 3D graphics, education, and MEA specialists to develop research-related MEAs with accompanying 3D-printed manipulatives. The purpose of this article is to provide a framework for engineering education teacher PD in authentic contexts and examine teachers' experience of the program, including comfort with and knowledge of integrated science, technology, engineering, and mathematics (STEM) instructional strategies. Pre-post survey results show high levels of satisfaction with the workshop and significant gains in integrated STEM understanding and comfort. Potential barriers to curriculum implementation include lack of a 3D printer and time. We provide a list of lessons learned from the PD development and implementation along with recommendations for developing similar PD programs.