A heat diffuser is a kitchen tool designed to distribute heat evenly across the bottom of a pot or pan. It helps prevent hot spots, which can cause food to cook unevenly or burn. Heat diffusers are especially useful when cooking delicate dishes that require gentle heat, such as sauces or custards. Typically made from materials like stainless steel or cast iron, heat diffusers can be placed on a stovetop burner before the cookware is set on top. They are available in various sizes to fit different pots and pans, making them a versatile addition to any kitchen.