Blue cheese dressing is a creamy, tangy dressing made by blending blue cheese into a mayonnaise or sour-cream base with seasonings such as garlic, Worcestershire sauce, lemon juice, and herbs. It emerged in the United States in the early 20th century as a dip and salad topping and became a fixture alongside fried foods.
Roquefort, Gorgonzola, and Stilton are the blue cheeses most often used; the ratio of cheese to base varies by recipe, with more cheese giving a sharper, more pronounced flavor. Some versions add bacon bits or chopped walnuts.
Blue cheese dressing is a common dip for buffalo wings and crudités and a topping for baked potatoes and burgers, in addition to its use on green salads. It's often confused with ranch dressing, since both are creamy American dressings served alongside fried chicken and wings; ranch is built on buttermilk and herbs with no cheese, while blue cheese dressing's flavor comes specifically from the fermented cheese itself.