Clabber is a food produced by allowing unpasteurized milk to turn sour at a specific humidity and temperature. Over time the milk thickens or curdles into a yoghurt-like substance with a strong, sour flavor. In rural areas of the Southern United States, it was commonly eaten for breakfast with brown sugar, nutmeg, cinnamon, or molasses added. Some people also eat it with fruit or black pepper and cream.Clabber was brought to the South by the Ulster Scots who settled in the Appalachian mountains. In fact, clabber is still sometimes referred to as bonny clabber (originally "bainne clábair", from Gaelic bainne - milk , and clábair - sour milk). Clabber passed into Scots and Hiberno-English dialects meaning wet, gooey mud, though it is commonly used now in the noun form to refer to the food or in the verb form "to curdle". A German version is called Quark. In France a similar food made from cream is known as crème fraîche.