Writing in mathematics is an essential skill for communication and many technical careers. Research suggests that writing in mathematics often leads to increased understanding and more effective communication. However, writing in mathematics is still underutilized as a method of instruction. Further, many college students practice example-based learning and often never fully comprehend fundamental mathematical concepts and how to communicate them well. To increase understanding of undergraduate mathematics topics, students should also be provided the prerequisite skills needed to communicate mathematical concepts well. This online course targets mathematical writing and communication. Specifically, the course utilized evidence-based methods to support learning in an online environment and to help students learn mathematical composition using LaTeX, while also developing their communication and understanding of mathematics.