Abstract Crystalline silicates form at high temperatures (>900 K) (refs. 1,2). Their presence in comets3,4,5,6 suggests that high-temperature dust processing occurred in the early Solar System and was subsequently transported outwards to comet-forming regions. However, direct evidence for this crystallization and redistribution in Sun-like protostars has remained unknown. By comparing James Webb Space Telescope mid-infrared spectra of the periodically bursting protostar EC 53 (ref.