The development of RBL-STEM learning materials for students’ metacognition improvement in producing herbal tea from the cascara

STEM approach in a research-based learning method that combines innovative research and learning. This research develop a research-based learning method based on STEM approach to improve students' metacognition skills in  utilizing cascara fermentation with a magnetic field to produce health herbal teas. This research and development was employed the ADDIE research and development model that consisted of five stages: analysis, design, development, implementation, and evaluation. In the analysis phase, interviews and observations were carried out based on the guidelines to identify the problems. The design of the product was then determined to be developed in the development stage, followed by the expert validation in the assessment stage to measure content validity and face validity. The implementation and evaluation stages produce the final product that was tried out to gain data of students’metacognition skills.  The product developed in this research is regarded valid, effective and practical. Besides easy use, the product can serve as essential lecture material. Keyword: Research based learning, STEM approach, Metacognition Skill;