In this self-study, we aimed to delve into how re-designing and teaching re-designed practicum course offered to pre-service teachers (PTs) enriched our, as science teacher educators, development of pedagogical content knowledge (PCK) for teaching science teachers. This self-study was conducted during a compulsory practicum course in which we served as teaching assistants (TAs). The qualitative data collected through journal entries written by the help of mentoring experience, Content Representation (CoRe), reflection papers, formal observations of PTs' teaching practices and microteaching each week, formal and informal meetings with PTs. The results were presented through vignettes that included an emphasis on a critical examination of our prior practices, the changes made in the practicum, and the difficulties that PTs faced. This self-study was valuable for us regarding the development of our PCK and building interplay among all PCK components. In light of the experience we gained, implications for science teacher education and research were provided.