We found that actively engaging students in our introductory microbiology course was a challenge given our large class sizes and many non-majors taking the course as a program requirement. Therefore, we introduced a novel active learning strategy to our course. Students grouped into teams of three had to create PowerPoint virtual posters on one of three themes: (a) a report on a microbe or immunology story in the news, (b) interview a research scientist, or (c) research a microbiological topic of their choice. To assess the intervention's effectiveness, a pre- and post-course assessment was done. Pre-posttest analysis revealed a significant drop in surface learning and rise in deep learning. Also, there was a drop in the extrinsic (grade-dependent) goal orientation and affective (test anxiety) components. We found a decline in task value, self-efficacy for learning and performance, organization, critical thinking, time and study environment, and help seeking in students' post-test scores. Qualitative findings also indicated the importance of group activity, gaining extra knowledge outside the curriculum, and long-term course content retention. In conclusion, we propose that the creation of digital posters in teams is an effective strategy to increase student engagement in large classes.