Morocco's fermented butter

Smen Is Morocco's Funky Fermented Butter That Lasts For Years - NPR foodways

If you get a hankering for cheese in the western Maghreb, you may be stuck with an (imported) Laughing Cow triangle wrapped in tinfoil.
Morocco doesn't have much of a dairy tradition, but there's one exception that dates back centuries: It's called smen, and it's a stinky, fermented butter made from sheep, goat or cow milk.
Tucked away in the heart of the Fez medina, there's a whole square dedicated to smen. Walk in, and you immediately get a strong whiff of butter. Vendors in Qaat Smen, or Smen Square, are part of families who have been making it for centuries. More recently, they've added honey, olive oil and khliyah — a rich, flavorful dried meat swimming in lard — to their wares. It's sort of "preserved stuff" square at this point, but it was smen that started it all.
Like Indian ghee, smen evolved as a way to keep a tasty cooking fat around for a long time. But while ghee is clarified to remove the milk solids and moisture, smen is fermented — which gives it its funky, cheesy aroma.