Even with increasing calls for both researchers and educators to attend to the "E" in STEM from within the larger field of STEM education, little is known about the practices that serve to support early educators' pedagogy and related content knowledge of engineering design. Using multiple methods in a revelatory, embedded, single-case design, this research provides an explanatory account of preservice teachers (PTs) engagement during a structured field experience with preschoolers designed to foster their understanding of design-based engineering though collaborative learning and teaching experiences. Research Findings: Findings reveal that the PTs developed more robust understandings of design-based engineering and stronger self-efficacy beliefs related to their practice following participation in the learning and teaching collaborative project. PTs also voiced concerns over perceived challenges of integrating engineering instruction within the pedagogically and content restrictive environments of contemporary early childhood classrooms. Practice or Policy: Additionally, this research suggests that guided teaching and learning partnerships can support early childhood teacher preparation programs in developing preservice teachers' understandings of the interrelationships between engineering and other aspects of the curriculum using emergent curricular approaches and interactional, play-based pedagogies.