Portfolio assessment is valuable for promoting reflective practice in student teachers. This paper describes how a university supervisor required her student teachers to select three professional goals at the beginning of their practicum and provide the proof that they achieved them by the end of the semester. The supervisor began by showing the student teachers her own first portfolio with its three goals. She explained the activity to the students using a handout. Student teachers were expected to select three goals that had personal meaning; make sure that the goals could be proven at the end of the semester; provide evidence of how they met each goal through artifacts such as notes, articles, handouts, dialogue, and observation; and write one page per goal of how each goal was met. The supervisor found that her student teachers used portfolios for many purposes, including identifying weaknesses and plans for growth and improvement; focusing on content; encouraging reflection of promising practices; solving problems; and reconstructing knowledge of the process of growth and learning. This paper provides examples of students' goals and responses to the activity. (SM)