I know that if this can be done, my Chowhound brothers and sisters will provide the answer.
I need a recipe substitute for buttermilk, since I just painfully discovered that the major dairies here in Japan don't manufacture the stuff, and hence, the Japanese and/or international grocery stores here in Tokyo don't carry it.
I've started jonesing for cornbread, hushpuppies, and buttermilk biscuits. All of the recipes I brought over, (or have found on the internet) call for buttermilk.
So, does anybody have a sure-fire substitution for 1 cup of buttermilk? BTW, haven't had any luck finding keifer (my sister's idea) here, so that one is out. Also, please don't waste your energy posting any substitutions that call for "add enough of 'X' until it tastes like buttermilk". I had it once, as a kid, and have never summoned the courage to try it since, so I don't have an objective clue as to what straight buttermilk tastes like.