Science, technology, engineering, and mathematics (STEM) integration is a desired outcome according to Next Generation Science Standards. However, learning to teach integrated STEM content has been challenging for teachers. Consequently, the purpose of this qualitative study was to describe how 16 preservice teachers enrolled in a mathematics methods course created integrated STEM lesson plans that incorporated an authentic engineering problem. Content analysis of the completed integrated STEM lesson plans used the Quality K-12 Engineering Education Framework to identify any characteristics of engineering. We found that 15 of 16 preservice teachers demonstrated at least an emerging ability to create an integrated STEM lesson that contained an engineering problem, constraints, a prototype or model, model testing, and data collection and analysis related to the model. We concluded that giving preservice teachers opportunities to experience engineering design problems could better prepare them to design and implement integrated STEM education in their classrooms. The findings from this study have practical implications for mathematics methods teacher educators who teach the pedagogy behind STEM education. This study also has theoretical implications because socially situated learning theory was extended to Model-Eliciting Activities and connected them to the K-12 Framework for Quality Engineering Education.