This type of chorizo sandwich is very popular in Argentina, Chile, Peru, Puerto Rico and Uruguay. The name comes from the combination of the names of its ingredients: a grilled chorizo and a crusty bread (in Spanish: pan) such as a marraqueta or baguette.
The Argentine choripán consists of a sausage made out of beef and pork, hot off the grill, split down the middle, and served on a roll. The chorizo may be used whole or cut in half lengthwise, in which case it is called a mariposa (butterfly). It is customary to add sauces on the bread, most likely chimichurri.
Choripanes are commonly served as an appetizer during the preparation of an asado, but they are also very commonly sold at sport venues (particularly football games) and on the sides of roads and streets in major cities in Argentina. Taxi cab drivers in Buenos Aires are avid consumers and some street sellers can gather a long line of cabs during lunch time and afternoons when drivers get their lunch break.