This article uses a self-study research methodology to explore teaching an online course for mathematics specialists. The course included weekly videoconferencing sessions and focused on supporting their development as mathematics coaches working with K-8 teachers to enhance mathematics teaching and learning. The central question for the self-study was about the design of the course and the characteristics of the learning environment that resulted from the design. The study included journal reflections and survey data. Three themes emerged in the analysis of the instructional decision making for the course: student autonomy and engagement, authenticity and practicality, and fostering community.