Butter salt

Butter salt is a seasoning developed in the late twentieth century for the purpose of combining the flavours found in salt and butter. It is a fine, golden powder, originally salt, enriched with butter flavouring. It is often used as a seasoning for popcorn. It is said to impart a "rich, buttery flavour".
The contents are usually salt, artificial butter flavoring, and yellow food colouring.
Use in butter.
Butter salt (sometimes called buttersalt) also refers to salt that is used in the preparation of butter and other dairy products. Some manufacturers produce salt specifically for the use in butter, such as "No. 2 butter salt". Salt serves as a preservative for butter.