While i google for the correct proportion of milk and lemon as to subsitute buttermilk for making key lime cupcakes. I got this result of how to make buttermilk..because i was searched wrongly by typing "how to make" instead of "what to subsitute"..Anyway, is good to have this result on how to make buttermilk as I still have a bottle of whipping cream in the fridge..
It was fun to make buttermilk and butter at home, like magic show..
1) Put 1 cup of dairy whipping cream / heavy cream in a empty bottle or jar (i was using the re-use Tauchew bottle).. Start shaking the jar back and forth. After several minutes, the cream will thicken and turn into whipped cream. So next time if you need a small portion of whipped cream, to serve with scones, pancakes, cupcake & etc, just follow this way rather than take out the big mixer to beat. Quick and fast..
2) Keep shaking until the whipped cream (quite heavy at this time) is replaced with a yellow glob (butter) and a separate liquid (buttermilk). I got buttermilk around 5tbsp and about 80g butter.
3) Pour/Sift the buttermilk out of the jar, and use it in any recipe that calls for buttermilk. If you need small amount of buttermilk in the baking, this should be the faster way instead of buying a big bottle.
To Use the Butter: Knead it under cold water for a couple minutes to remove any remaining buttermilk (it will spoil very quickly, if you don't). Then, salt (if desired), and store in the refrigerator until you're ready to use it.
Happy Baking !!