A centerpiece of teacher preparation is pre-service observation/supervision; however, with an emphasis on ratings (Mercado and Baecher, Global Educ Rev 1(3):63–77, 2014), observations tend to be evaluative in nature rather than developmental. In developing teachers, there is a great need to emphasize evidence-based reflection (Farrell, Reflective practice in ELT. Equinox Publishing Limited, 2019). In heeding this call, this study implemented an interventionist conversation-analytic framework called FAB (Waring and Creider, Micro-reflection on classroom communication: A FAB framework. Equinox, 2021) over a series of five post-observation meetings (POMs) across one academic year with a pk-12 pre-service English as a New Language teacher (ST). FAB compiles the conversation-analytic findings from classroom discourse research into three strands to be used for interventionist purposes: fostering an inviting environment, attending to learner voices, and balancing competing demands. Each POM was conducted via Zoom and used the GoReact software to allow the supervisor (SUP) and ST to collaboratively micro-reflect on STs’ teaching video using FAB as a lens. The data were analyzed using Conversation Analysis (CA) to uncover any longitudinal changes in ST’s conduct in the POMs. The findings document three main changes: (1) ST shifts from relying on her memory to relying on the video evidence when introducing teaching video clips to be replayed in the POM, (2) ST shifts from hypothetical claims and conjectures to evidence-based observations in making noticings about her teaching, and (3) ST shifts from making top-down references to FAB to eventually no reference as she improves her ability to micro-reflect. Overall, as ST learns to ground her development in the evidence afforded by the teaching video, there is a greater sense of agency in the POMs and less reliance on the SUP to drive the interaction.