The use of augmented reality (AR) in cultural heritage (CH) applications opens a whole set of possibilities, including the virtual transformation of CH elements. This paper presents TinajAR, a mirror-based AR application designed to serve both as an edutainment application in the field of CH and also as an artistic expression. As an edutainment application, TinajAR features a multi-marker video-based AR application designed to show virtual ceramic pieces and explain the pottery process through virtual avatars. As an artistic expression, TinajAR seeks to reinterpret an ancient type of cellar called calado, which was used in the past for storing wine in northern Spain. The reinterpretation consists in giving a different but meaningful use to the space. TinajAR was used by around 1800 people during a ceramics exhibition in La Rioja, Spain and was assessed at the satisfaction level with 56 users by means of a system usability scale, giving very satisfactory results.