In the era of AI, engineering education is undergoing a transformative shift. With knowledge readily accessible online and AI increasingly automating engineering tasks, traditional discipline-specific knowledge transfer is no longer sufficient. The key challenge for educators is to cultivate holistic engineers with humane qualities that AI cannot replace. In the past decade, we have created an interdisciplinary approach to engineering course development that combines design thinking, software development, and practical skills to produce well-rounded engineers. This paper introduces a three-layer framework for interdisciplinary engineering course development. The foundational layer establishes the theoretical basis for holistic development, emphasizing knowing for self-awareness, doing for practical application, being for moral and ethical growth, and becoming for personal and collaborative innovation. The middle layer incorporates rapid, iterative problem-based learning (PBL) as a scaffold for curriculum design. Finally, the top layer focuses on student achievements, highlighting the cultivation of professional, civic, and ethical responsibilities that underpin holistic growth. To illustrate the framework in action, the course ``Interdisciplinary Innovation Methods and Practices'' is presented as a case study. Course evaluations reveal that students achieve academic and professional growth and develop a strong sense of civic and social responsibility. Additionally, this paper offers practical recommendations for curriculum design and pedagogy while discussing limitations and future directions for refining the framework. This approach equips engineers to tackle interdisciplinary challenges in an AI-driven world while fostering the humane qualities essential for societal progress.