Matambre is the name of a very thin cut of beef in Argentina and Uruguay, taken from between the skin and the ribs, a sort of flank steak.
The same word (or matambre arrollado or matambre relleno) is also used for a dish made of a matambre meat roll stuffed with vegetables, hard-boiled eggs and herbs, then boiled or oven-roasted. It is served sliced—with the fillings making a colourful display—either hot or cold. It is often eaten with chimichurri sauce. It is a rather fatty meat and is usually eaten with vegetables. Pork matambre is also used.
The name matambre is a portmanteau word, "matar" + "hambre" ("kill hunger").
Matambre is cut from the same place that the flank steak is cut from in U.S. cuts. It is taken from the lower part of the cow and is part of the diaphragm muscle of the cow. It is the outer portion of the muscle where the muscle attaches to the body wall.
In Argentina, the matambre is sometimes served as a steak, but this is not the typical serving method. The more common method is known as "matambre relleno" (stuffed, or filled matambre). The ingredients for this dish vary from province to province, but most common include whole carrots, hard-boiled eggs, and plenty of black pepper. These ingredients are then rolled up inside of the matambre sheet and sewn or pinned together to keep the rolled matambre from coming unrolled. It is then boiled in milk, or sometimes water, and roasted in the oven. After it is removed from the oven and cooled, it is sliced into thin pieces of lunch meat and served in toasted French roll with mayonnaise, and sometimes Argentine chimichurri, as a condiment. In Uruguay, and to a lesser extent in Argentina, matambre is marinated in milk, baked flat in the oven, and covered with the marinade, with the addition of lightly beaten eggs and cheese at the end of the cooking period. It is called "matambre a la leche" (matambre in milk). Another method of serving matambre is "matambre a la pizza" which is prepared in a similar way but instead of being rolled it is topped with pizza ingredients like tomato sauce and mozzarella.