What is “cultured” butter?

LMGTFY

Butter that spent a semester abroad.

Well, I came here to tell you it is well read in the classics, but that has been taken, so I'll say, the unprocessed whole milk is pasteurized (to comply with US Law) and then has bacterial cultures added as if they were going to make butter milk and then set aside for maybe 24 hours. During that time, it develops a "tang", the taste of buttermilk. Then the butter is separated from the milk, just like regular butter production. The resulting butter has a mild "Tang" or "Sharpness" of taste.

Telling you it was proficient in arts and the classics would have been funnier.

Spankum - hard to not take a strong swing at a low outside pitch.