Smen, Smenn, Smeun

Smen is a kind of clarified butter used in Arab and Magreb cooking. The concept dates back to time immemorial as a way of preserving fat in hot climates. Incorrectly called "rancid butter" by Europeans, it is usually made from sheep's milk, sometimes from cow's milk or even buffalo milk in Egypt. 

The butter is liquefied and clarified; a little salt and sometimes some couscous is added and it is stored in a clay or earthenware pot. It is left to age so that its flavor mellows and it takes on a nutty note. 

It is used both for cooking couscous and tagines as well as for pastries.