This sequential explanatory mixed methods study (quant + QUAL) examined elementary preservice teachers' conceptions of teaching engineering. Participants (n = 104) from two large western universities completed the Draw-An-Engineering-Teacher-Test (DAETT) as part of their elementary science methods course. Additionally, a subgroup of participants (n = 34) engaged in a case-based reasoning intervention around engineering design-based teaching, while remaining participants (n = 70) did not. No significant differences were detected between the two subgroups for DAETT scores. Upon examination of DAETT for evidence of engineering design-based teaching, it was noted that participants in both groups gravitated towards specific constructs of engineering design, such as building and testing, while constructs such as student problem scoping and optimization were less likely to be represented. Participants from both groups also conflated science and engineering, with roughly half of participants' drawings being void of engineering design-based teaching. The drawings that lacked evidence of engineering design often exhibited characteristics of traditional science teaching (e.g., teacher lectures or demonstrations of science concepts). Preservice teacher artifacts indicated an increase in participants' breadth of knowledge around engineering teaching but not their depth of knowledge on the topic. Researchers argue this evidence supports the need for primary school science methods courses to include additional opportunities for engineering engagement.