Professional development for astronomy instructors largely focuses on enhancing their understanding of the limitations of professor-centered lectures while also increasing awareness and better implementation of learning strategies that promote a learner-centered classroom environment. Given how difficult it is to get instructors to implement well-developed and innovative teaching ideas, even when these instructors are supplied with significant and compelling education research data, one must wonder what is missing from the most commonly used professional development experiences. This article proposes a learner- centered approach to professional development for college instructors, which we call situated apprenticeship. This novel approach purposely goes beyond simple awareness building and conventional modeling, challenging instructors to actively engage themselves in practicing teaching strategies in an environment of peer review in which participants offer suggestions and critiques of each other's implementation. Through this learner-centered teaching and evaluation experience, instructors' preexisting conceptual and pedagogical understandings of a particular instructional strategy are brought forth and examined in an effort to promote a real change of practice that positively impacts both their core pedagogical content knowledge and their skills in successfully implementing these teaching strategies. We believe that the adoption of our situated apprenticeship approach for professional development will increase the frequency and success of college instructors' implementation of research-validated instructional strategies for interactive learning.