There is increasing interest in the application of game-based learning approaches to education. Educators across a wide range of contexts are using digital games such as educational escape rooms to promote learner motivation and support skills development. Whilst the literature describes multiple game-based learning theories that can underpin such strategies, there is little practical guidance on how to integrate such conceptual elements into the design of digital educational escape rooms. This study aims to address this gap, outlining the use of an online design-thinking process to plan, build, and test a digital educational escape room. Our findings suggest that this process provides an effective way of harnessing team collaboration and innovation in the development of digital educational resources. The process provides structure for game design teams, enabling them to address complex or "messy" educational development problems. In utilising an online design-thinking process to design games for learning, we make a number of recommendations. These include taking time to establish psychological safety within the design team so as to facilitate creative team processes and supporting team members to adopt a design-thinking mindset throughout (e.g., regularly taking the perspective of the game user, and testing game prototypes early and frequently). Finally, our study offers a detailed description of how the online design-thinking process can be applied in an education context with the aim of offering guidance to educators and students who may want to design, build, and test their own digital educational escape rooms.