Unless you have a cheap and plentiful supply of cream – a cow grazing in the garden, say – you're unlikely to want to make your own butter day in, day out. But for a special occasion, to go alongside homemade crumpets or sourdough bread, perhaps, it's the icing on the cake.

For 400-450g of butter you'll need 900ml double cream. Let this come to room temperature while you prepare a few litres of ice-cold water. Use some of this to chill a large mixing bowl, two stiff spatulas and the blades of an electric whisk. Empty out the mixing bowl, pour in the cream and beat it at a medium speed for about 10 minutes. First the cream will thicken, then it will make soft peaks and eventually it will become stiff and form crumbly-looking clumps. Keep on whisking and suddenly you'll find a whitish liquid pooling at the bottom of the bowl. The liquid is buttermilk, which you can drink or use in baking.

Carry on whisking for a minute or two, until there's no more liquid to liberate, then remove the whisk. Strain the cream into a container and put it in the fridge. When you have time to use it, Yotam Ottolenghi and Felicity Cloake have some lovely recipes for tarts, cakes and pancakes .

Now you need to wash your developing butter of any remaining buttermilk, which will make it spoil more quickly. Pour in enough ice-cold water to cover the butter comfortably and use the spatulas to press it down as hard as possible. You'll quickly see that the water you poured in becomes cloudy. Tip this away and repeat the washing and squeezing process five or six times until the water runs fairly clear. Don't be afraid to lift up and turn the butter as you go, but work as fast as you can so it doesn't have time to heat up.

Once the washing is finished, sprinkle over a teaspoon of crumbled sea salt (if that's the way you roll, butter-wise) and either shape the butter into two or three blocks with the spatulas, or cram it into a couple of glass pots. It will keep for a week in the fridge, or six months in the freezer.

Phil Daoust is a food writer based in England and France. twitter.com/philxdaoust