Add cream to a mixing bowl, or the bowl of an electric mixer, and whisk until the solids and liquids separate. This can take from 10 – 30 minutes.
Once separated, strain and add the butter to a muslin cloth or clean towel and squeeze to extract the excess buttermilk. Save this for another recipe.
Return the butter to the mixing bowl and mix with approx. 125ml of iced water, until almost combined.
Strain and squeeze the excess moisture through the cloth or towel.
Repeat this process at least one more time, until the drained water is clear.
At this point, optionally mix with a pinch of salt, portion, wrap and store. The butter will last for 3-4 days in the fridge, or can be frozen.