Easy to do, and weirdly satisfying.
- Double cream
Put the cream into a jam or kilner jar and firmly attach the lid.
Shake vigorously for 5 – 10 minutes, the cream will thicken, then suddenly start to slosh around as the buttermilk separates from the butter.
Drain the buttermilk, and shake again for another minute to remove the last of the buttermilk, before draining one last time.
Optionally you can now season with salt or try adding herbs or garlic to the butter.
The buttermilk can be used for making cakes or biscuits.