butter prepared without salt (which acts as a preservative)
The difference in price is due to the fact that unsalted butter spoils readily.
Caution: Do not attempt to convert modern salted butter into unsalted butter by washing it.
It was with unsalted butter it was used, but I don't know what the words were.
Put some sweet, unsalted butter in a frying pan—enough to swim the mushrooms in.