In response to the COVID-19 pandemic, K12 districts implemented online professional development (PD) programs to support teachers' online teaching skills, knowledge, and self-efficacy. Many of these programs, however, over-relied on content delivery and failed to provide an online learning environment ripe for developing teachers' self-efficacy. We designed and implemented an online PD program focused on application and community building to lessen the bridge between content and practice, and to increase teachers' Online Teaching Self-Efficacy (OTSE). We present results from an explanatory mixed methods study of 61 classroom teachers in a Mid-Atlantic public school district. Our goal was to understand how and why participating in this PD program led to an increase in OTSE. This paper concludes with contributions for online teacher PD.