MWrite is a project that implements writing-to-learn pedagogies in large-enrollment introductory undergraduate courses to facilitate student understanding of challenging course concepts and disciplinary thinking. Faculty members and MWrite staff develop prompts that ask students to explain these concepts via real-life problems or projects taken up by specialists in the field. Writing Fellows, undergraduates who previously took the course, work with faculty to revise prompts and to support students in brainstorming, drafting, writing, peer reviewing, and revising responses to these prompts.