Online learning and teaching is rapidly increasing in many countries, including high schools in the USA and teacher education worldwide. Online and blended approaches to professional and organizational development are, therefore, becoming essential to enable effective and equitable education. Authentic project-based learning to support the evolution of best practices in online and blended learning in the professional contexts of the students is the current practice shared in this paper. Through a description of our postgraduate course, its pedagogy and student artifacts, its impacts are illustrated in K-12 schools and teacher education within and beyond New Zealand. Authentic online formative assessment is at the core of the pedagogy described. (Contains 1 table and 1 figure.)