Planning is a central task of teaching and a central focus in learning to teach. But what does planning entail, and how is planning best learned? What challenges do experienced teachers serving as school-based teacher educators face in becoming teachers of planning? What role can university teacher educators play in helping mentor teachers learn to teach planning? As John (2006) notes, "How to plan well remains a knotty but crucial topic for teacher education research and practice." This article examines these questions by drawing on empirical data from a larger study where the author examined how to reconfigure her role as a university field supervisor to support classroom teachers in learning the practice of field-based teacher education over a one-year period. (Contains 1 figure and 2 notes.)