This design case describes the blueprints of an electronic development portfolio (PERFLECT) aimed at supporting the development of self-directed learning skills, including self-assessment of performance on learning tasks, formulation of points for improvement and future learning task selection. The design is described both in terms of theoretical foundation and practical characteristics. As part of the design process a small-scale evaluation study with 22 students of senior vocational education was conducted. Students hold positive perceptions about PERFLECT's ability to help them self-assess their performance on learning tasks and formulate points for improvement. Furthermore, they were also satisfied with PERFLECT's usability and user-friendliness. However, students request a simplification of language use and need more support and guidance with the selection of criteria for performance assessment. Suggestions for improvement will be incorporated in the next iteration of the design. PERFLECT is a promising, user-friendly tool to support students' development of SDL skills.