Virtual learning environments offer new possibilities for technology enhanced teaching and learning, but providing rapid, individualised feedback for complex assignments in large student groups remains challenging. This paper presents a Formative Assessment Management System (FAMS), a computer-based tool for teachers to generate written feedback at scale with minimal overhead. FAMS leverages archived feedback fragments and thematic identifiers to create pertinent feedback while consistently maintaining quality and fairness. The system has been implemented in programming courses and yielded promising results, including reduced feedback delivery time and maintained feedback quality. Future research will evaluate FAMS from student and teacher perspectives, conforming to educational action research, continuous quality improvements, and investigating correlations between aspect-based assessment and learning outcomes.