Contribution: A flipped classroom approach to teaching empirical software engineering increases student learning by providing more time for active learning in class. Background: There is a need for longitudinal studies of the flipped classroom approach in general. Although a few cross-sectional studies show that a flipped classroom approach can increase student learning by providing more time for other in-class activities, such as active learning, such studies are also rare in the context of teaching software engineering. Intended Outcomes: To assess the usefulness of a flipped classroom approach in teaching software engineering. Application Design: The study was conducted at an international master's program in Sweden, given in English, and partially replicated at a university in Africa. Findings: The results suggest that students' academic success, as measured by their exam grades, can be improved by introducing a flipped classroom to teach software engineering topics, but this may not extend to their subjective liking of the material, as measured by student evaluations. Furthermore, the effect of the change in the teaching methodology was not replicated when changing the teaching team.