This paper conceptualises Education for Sustainable Development (ESD) as a Wicked Problem and highlights the need to explicitly address its inherent controversy in geography teacher education. To engage with the content-related, pedagogical, and structural dimensions of this Wickedness as they intersect in everyday classroom practices, we propose multimodal vignettes as a promising casuistic tool for reflection. Drawing on the international project INTERACT, the paper outlines the construction of these vignettes and illustrates the approach through one specific vignette. First experiences from using the vignette corpus in different seminar contexts suggest that multimodal vignettes may support a shift away from solution-orientated approaches towards more reflexive engagement with the complexity, uncertainty, and contested nature of sustainability-related teaching.