Final answer:
True, cornstarch should be mixed with a cool liquid to create a slurry before being added to hot liquid to prevent clumping and ensure smooth thickening.
Step-by-step explanation:
True, cornstarch should be mixed with a cool liquid before being added to a hot liquid. This is an important step in the cooking process known as making a slurry. A slurry is a mixture of a starch (in this case, cornstarch) and a liquid, which is used to thicken sauces, gravies, soups, and other dishes.
If cornstarch is added directly into a hot liquid, it can clump together and form lumps, creating an unpleasant texture. By first mixing it with a cool liquid, the cornstarch particles are evenly dispersed. When this slurry is then incorporated into the hot liquid, it thickens evenly without clumping, resulting in a smooth and consistent final product.