The Subject is Writing
Are you familiar with WAW pedagogy in writing scholarship? Click on the Wardle and Downs book for a useful bibliography on it.
For a number of semesters I’ve been using the Writing Spaces: Readings on Writing anthologies in two of my courses, and its plausible to believe the argument that Writing About Writing can address the long-time concern of writing skill transfer beyond a composition class.
By the way, Writing Spaces is freely distributed under a Creative Commons license, so adopting it provides an immediate solution to the over pricing of college textbooks.