Caul fat – also called lace fat – is a thin, fatty membrane which surrounds the internal organs of some animals. It has a lacy, semi-transparent appearance and is used to flavor dishes as well as wrap meats.
Sheep caul fat is particularly common in Morocco, and many families save the caul fat after a home slaughter, particularly during Eid Al-Adha. The caul fat can be used to flavor kefta (ground beef and/or lamb), as well as fillings for Kefta Msemen or Onion Msemen. It's also used by many families to make liver brochettes called Boulfaf.