Blue cheeses are a type of cheese that is characterized by the presence of blue or green mold, which is created by the addition of specific cultures of Penicillium mold during the cheese-making process. This mold gives the cheese its distinct flavor and appearance, often resulting in a creamy texture with a sharp, tangy taste. Common varieties include Roquefort, Gorgonzola, and Stilton. These cheeses are typically aged in caves or controlled environments to enhance their flavor development. They can be enjoyed on their own, crumbled over salads, or paired with fruits and nuts. The unique taste of blue cheeses makes them a popular choice for cheese boards and gourmet dishes.