Eliciting and responding to student thinking are high-leverage practices that have powerful implications for student learning. However, they are difficult to enact effectively, particularly for novices, and more research is needed to understand how teacher education can support teachers in developing these skills. This study examined ways prospective elementary teachers (PSTs) responded to unanticipated incorrect student solutions to high-demand problem-solving tasks and how their responses changed over a 6-week field experience embedded in a practiced-based mathematics methods course. Data were collected in 6 weekly cycles of planning (written plans), enactment (video of problem-solving sessions with students), and reflection (written reflections on video). Problem-solving task implementations were analyzed using cognitive demand and math-talk frameworks. Of the three collaborating PST groups, two groups improved at responding to unanticipated incorrect solutions, but these two groups also developed a tendency to shut down anticipated solutions. The third group showed no patterns in their responses to unanticipated incorrect solutions, but did maintain the cognitive demand when responding to anticipated solutions. I present a case of one group of collaborating PSTs who made improvements in responding to unanticipated incorrect solutions in terms of the pedagogical moves they employed, cognitive demand associated with their responses, and how their responses changed over time. Implications for teacher education are discussed.