This paper applied an adapted design sprint approach, called a design summit, to educational prototyping. Design sprints provide a structure for applying design thinking and capturing user requirements that can be adapted to the needs of varied design contexts. However, finding a format that meets project requirements and brings in diverse stakeholders while also considering their availability can be difficult to construct using a traditional design sprint approach. Through four adapted stages of understanding, defining, iterating and prototyping towards a problem space, this paper presents a case study of a design summit applied to education/instructional design, specifically towards the problem of designing teacher professional development on the topic of the high ability (HA) student. A key feature in our applied approach is using concurrent prototyping, over many months, to achieve project outcomes. The case study presents the process and challenges of developing educational resources suited to the professional development of teachers and school leaders that need to support HA students. Through iteration, the results show how diverse stakeholders engaged and provided feedback to inform prototyping outcomes. Our design summit case study demonstrates how careful planning, focused elicitation of user requirements and an elongated and concurrent prototyping process results in outcomes that meet education stakeholder expectations and align with project requirements.