Cognitive phenomena have been recognized as important to understanding entrepreneurial action. Mentoring has been promoted as a critical ingredient in evolving the entrepreneur’s business model while correspondingly evolving the entrepreneur’s cognitive development toward a more expert entrepreneurial mind. There is minimal empirical research on the effect of customized mentoring on how entrepreneurial cognition co-evolves with the new venture’s business model during the development of entrepreneurial opportunities. To address this gap, we empirically investigated the effect of intensive mentoring and feedback on cognitive development of entrepreneurs during their strategy formulation phase, while we simultaneously measured changes in how they value, acquire, organize and deploy resources.