This article revisits the notion that to facilitate quality learning requires teachers in higher education to have pedagogical content knowledge. It constructs pedagogical content knowledge as a teaching and learning space that brings content and pedagogy together. On the content knowledge side, it suggests that threshold concepts, akin to a portal that opens up a new and previously inaccessible way of thinking about a subject, are useful in quality learning. On the pedagogy side, it employs student engagement as a useful proxy for identifying what happens in a learning environment to achieve quality learning. This article asks "what fresh insights might this particular conceptualization of pedagogical content knowledge afford teacher education and teacher development in achieving quality learning in higher education." After outlining characteristics of threshold concepts and student engagement, it brings together the contributions these concepts make to pedagogical content knowledge before detailing some fresh insights afforded by the synthesis. (Contains 1 figure.)