Curved folded structures, created through folding, bending, and joining non-rigid sheets, are widely employed as decorative components. However, their functional applications remain limited, as the modelling process can be time-consuming and computationally intensive, and designing structurally sound curved folded structures presents another layer of complexity. This study introduces a new type of curved folded structure, which can be automatically designed by topology optimisation algorithms through stiffness maximisation and straightforwardly constructed using simple curved folded sheets. The design technique uses the mirror reflection principle to transform optimised topologies into their corresponding curved folded forms for efficient load paths. A series of examples are presented to demonstrate the effectiveness of the design-to-reality workflow. Finite element simulations are performed to reveal the performance of optimised curved folded structures.