Your recipe calls for buttermilk but you don't have any?
Add 1 tablespoon of lemon juice or white wine vinegar to whole milk and sest aside for 10 minutes. The curdled milk will work as a perfect substitute.
In Good Housekeeping, October 2015
I was always making notes on scraps of paper about tips and facts I'd read in books and magazines, seen on the Internet or on TV. So this is my paperless filing system for all those bits of information I want to access easily. (Please note: I live in the UK, so any financial or legal information relates only to the UK.)