This article describes how the design of digital learning objects can spark professional learning. The challenge was to build learning objects that would help experienced special education teachers, who had been teaching in math classes, to demonstrate their proficiency in middle and secondary school mathematics on the PRAXIS examination. While the learning sciences have focused on questions of learning new knowledge, the context of how adults recover information they had once studied has received less theoretical attention. The authors' thesis is that a central aspect for helping students to remember content they once learned is to uncover areas of "conceptual breakdown" in ordinary math problems. Their theory is that the phenomenon of conceptual breakdown is different for remembering knowledge than for learning new knowledge. Remembering math involves reassembling misplaced, broken or fragmented conceptual knowledge once learned in school. The design of learning objects allows us to determine which aspects of PRAXIS-type questions highlight conceptual breakdown, and leads us to build learning objects that would help learners reassemble prior concepts to improve capacity to solve similar problems. This article reports on a design-based research investigation to build, implement and assess a series of math learning objects for adult learners. Twelve web-based learning objects were built over the course of 2 years, and tested with 59 adult learners. The authors discuss how the collaborative design process was structured to elicit the breakdown points present in typical math problems; describe an assessment process that produced pre- and post-learning results; and comment on how the design process illustrated their theory of adult math learning recovery and on the prospects for designing learning objects for adult learners.