This document discusses teacher professional development and the theory-practice dichotomy in mathematics education. It provides an overview of the relevant literature on this topic and examines different models that have been proposed to describe the relationship between theory and practice. It then describes an initiative in Germany called "Mathematics Done Differently" which aims to better address teachers' needs through innovative approaches to professional development, such as offering courses tailored to teachers' specific requests. The document concludes by reflecting on the successes and challenges of this approach to bridging theory and practice.