Reports of flipped classrooms across areas in the field of ESL are rare, and those that address the complexities of ESL teacher education, particularly the methods course in which procedural knowledge is privileged over declarative knowledge, are even rarer. This paper uses a design-­-based research (DBR) approach to explore the flip of an ESL teacher education course for mainstream teachers. This study, focusing on the five members of the design team, seeks to fill several gaps in the literature: the lack of design specifics; data on the use of flipped instruction in teacher education; the need for examination of flipped teacher education contexts. The paper, formatted in the style of DBR, provides suggestions for design steps, data sources, and principles for the design of teacher education courses.