Doctoral supervision is complex and takes place against a background of contextual, political, economic, and cultural affordances/constraints; with multiple purposes; and in a global higher education system. The result can be significant tensions for supervisors and, often, poor student satisfaction and progression. Globally, systematic development of doctoral supervision capacity is unusual and/or prohibitively expensive at scale. In response, this paper reports an educational design research initiative to develop a series of collaborative online workshops for experienced doctoral supervisors, supporting deliberate 'reflective, personal, scholarly and systematic reflection' across ten areas of doctoral supervision. Participants are then well-equipped to craft a successful application for the prestigious United Kingdom Council for Graduate Education supervisor recognition. Our evidence suggests short-term benefit is in two phases: directly via collaborative workshop engagement with the supervision literature in relation to participants' shared experiences of supervision, and then via application of that to practice, captured in semi-structured scholarly reflective accounts on development of practice in submission for accreditation. Embedded medium-term benefits are now emerging. Multiple iterations suggest the approach is sustainable, transferable, affordable, and richly beneficial to participants, doctoral students, and wider doctoral communities. The contribution is to development of academics' teaching and research, and it is both theoretical and practical.