Place cream into Thermomix bowl and warm for 5 min/37°C/speed 2.
Add yoghurt or creme fraiche and stir through for 15 sec/speed 2.
Pour into warmed, sterilised glass jar or Thermos flask and keep at temperature for 12 hours. The glass jar must go into a yoghurt maker or similar to stay warm…this can be up to 24 hours or even longer, within reason…a week is too long.
Chill the newly cultured cream until totally cold…colder the better.
Return cream to a COLD Thermomix bowl with Butterfly attached. Whip until separation occurs. This took a long time for me, and I think it is something to do with the heating of the cream previously. Drain off the buttermilk after you have separation and voila, you have Cultured Buttermilk as well…(cultured butter, ergo; cultured buttermilk from the butter!!)
Wash the butter by removing the Butterfly and pouring into the Thermomix bowl, plenty of icy cold water. Close the lid and wash for 20 sec/speed 5, occasionally hitting the Reverse function so that you get a washing machine action!
Remove liquid from butter by squeezing, add flavorings of choice (salt, sugar, honey, cinnamon, chilli, garlic, truffle, need I go on?) and pot the butter into small bowls or dishes. Freeze until use, or not, depending on how fast you will eat this new treat. I have to say, I would probably not use this in cooking as it is a bit of a fiddle, but for beautiful home made, grainy, sourdough bread, or the aforementioned baguettes... I'm there baby!