Authentic assessment -- where instructors create a realistic, cognitively challenging learning environment -- is critical in environmental science education. However, academic staff insufficiently rely on best practices in authentic learning due to lack of knowledge or interest. Here, we evaluate existing frameworks to improve the authenticity of higher-education courses by applying them to an environmental science course and evaluating its authenticity and effectiveness. Our evaluation relies on qualitative and quantitative data obtained from student surveys, as well as students' reflective journals. We found that the course generally met the criteria of authenticity (realism, cognitive challenge, and evaluative judgement) and that students exhibited positive cognitive, affective, and behavioural responses to the course. Our research suggests that existing frameworks and tools can usefully support the evaluation of authentic assessment, although additional efforts are needed to lower barriers for non-expert academic staff to engage with the recent literature on authentic assessment and improve students' experience.