I came across this article the other day which shows how to make your own butter. It’s not something I have ever tried but looking at the instructions it doesn’t look that hard. So that I can find it again I am posting a link to it here.
The recipe which makes 1kg of butter and 1 litre of buttermilk starts off with 2.4 litres of double cream and 2 teaspoons of dairy salt which it says are optional. The cream is then whisked in a food mixer until thick and then even more until it separates into buttermilk and butterfat globules. The mixture is then turned into a sieve to separate the buttermilk and the butter whisked further to expel any remains of buttermilk. The sieving process is repeated. The butter is then kneaded with butter bats (wooden paddles) to remove any traces of buttermilk before being drained and washed several times. It can then be chilled or frozen.
It all sounds very easy and I will be trying it so watch this space for the results.