Using active learning methodologies with large classes in higher education is a complex task. Lecturers often lack the tools they need to guide their students, while also taking into consideration their individual needs. This study proposes an expandable strategy for introducing active learning following a metacognitive approach involving problem-based learning and anonymous peer assessment. The approach was implemented over two sessions as part of a 16-week business management class taken by 223 students. The results reveal that students were able to develop both their management and critical thinking skills at the same time. The main contributions of this paper are: 1) a metacognitive approach, where students discovered their own knowledge gaps and developed their critical thinking skills, and 2) an active learning approach suitable for large classes, where students received teacher guidance and individualised feedback from their peers.