Combine the granulated sugar and cornstarch in a high-speed blender. Blend on high for approximately 30 seconds or until the mixture reaches a soft, powdery consistency. The cornstarch helps prevent clumping and ensures a smooth texture.

Transfer the freshly made powdered sugar to an airtight container to maintain its light and fluffy quality. If any lumps form over time, simply sift the sugar before use for a perfectly fine texture. Use as needed in baking, frostings, or dusting over desserts.