Icing sugar, or powdered sugar, has a history that aligns with the history of sugar itself. Sugar was first produced from sugarcane plants in India and China around 2500 BC. However, the process of making icing sugar, which involves grinding granulated sugar into a fine powder and often adding an anti-caking agent like cornstarch, developed much later as sugar became more widespread and techniques for processing it evolved. The exact origin of icing sugar as a distinct product is not well documented, but it has been a staple in both baking and cocktail-making for centuries.