This article focuses on teacher educators’ reflections on prospective teachers’ cognitive engagement in the teaching and learning of mathematics during the pandemic. Using three interacting aspects that can foster learners’ cognitive engagement as a lens, observations and reflections from two teacher educators and anonymous screenshots of students’ work were gathered and analysed by a mathematics teacher educator. The prospective teachers’ self-regulated learning, engagement in solving tasks, and participation in productive discourse were positively surprising, showing the cognitive presence of the learners during virtual teaching. The influence of digital platforms like Blackboard and digital tools like GeoGebra, Desmos, Padlet, Google Docs, Google Forms and Google Sheets in teaching helped us observe the learners’ cognitive engagement in real time.Contribution: The GeoGebra Class function and the Desmos Teacher feature helped us to observe the prospective teachers’ cognitive engagement during the online teaching. However, continuously and rapidly creating digital content on said digital platforms can be demanding for educators.