Applying user-centered design skills is a critical aspect of engineering practice, yet integrating it into engineering education remains challenging. We have observed a need for straightforward, structured tools that facilitate early-stage engagement in user testing. In response to this need, the User Testing Toolkit was developed at Aalto university as a part of a collaboration of three universities located in Chile, Colombia and Finland. The partnership was set up to produce teaching tools that balance global relevance with local adaptability. The toolkit includes modular templates designed to guide students through the pre-testing, during-testing, and post-testing phases. Additionally, an expansion pack introduces fictional users and products, enabling practicing and refining testing methodologies in diverse scenarios. Piloted in multidisciplinary settings in Finland and Chile, the toolkit provided practical insights not only into student learning but also into how educators adopt and adapt new pedagogical tools. This practice paper presents the User Testing Toolkit as a concrete example of cross-institutional collaboration and highlights its dual role: enhancing student learning and strengthening the educational competencies of engineering educators in user-centered, practice-based learning contexts.