Mix the cream and yoghurt together in a large mixing bowl. Cover with cling film, then leave in a warm place for 36 hours. If you’d like an even tangier flavour to your butter, you can leave it for a further 12 hours

Once fermented and bubbles have formed, place the bowl into the fridge for at least 4 hours to chill completely

Make sure you have a large, clean work surface to prepare your butter. You will need a stand mixer with a paddle attachment (or electric hand mixer), a colander set over a bowl, a bowl of cold water and a dough scraper

Transfer the chilled, set cream mixture to the stand mixer (or into a large bowl if using a hand mixer)

Beat at a medium speed for around 5 minutes, until the buttermilk starts to separate from the fatty solids. At first it will seem like not much is happening, but suddenly the solids and liquids will begin separating – take care as it can start to splash

Once it looks like the butter curds have separated completely from the buttermilk, pour the mixture into the colander to separate the liquids and solids. Use your hands to squeeze the curds to extract as much buttermilk as possible

Place the solids back in the stand mixer (or bowl) and reserve the buttermilk, which can be used in all sorts of recipes (try using it to make scones or as a marinade for fried chicken). Give the solids another mix with the paddle or hand mixer for a few minutes to extract any remaining liquid, then strain once more

Use your hands to wash the butter in the bowl of cold water, squeezing and kneading it to remove the final remnants of buttermilk. Change the water several times and keep doing this until the water stays clear

Take the butter out of the water and place it on your work surface. Continue to squeeze and knead the butter, wiping the surface regularly to keep it dry and remove moisture

Transfer the butter to a clean tea towel and squeeze it to remove as much moisture as possible. Wipe your work surface again to make sure it is completely dry

Place the drained, squeezed butter on the dry work surface and spread it out using your hands or a dough scraper

Sprinkle over the salt, then use the dough scraper to knead it in – you want the salt to be evenly and very well mixed into the butter, as this will help to extend its shelf life as well as seasoning it. At this point you could also add any other flavourings you fancy, such as spices, herbs or garlic

Now it’s time to portion and shape the butter. A good way of doing this is to roll it into logs, then use the scraper to divide it into small equal portions

If you have them, use wooden butter paddles to create small rounds or use your hands to roll or shape them however you like. Wrap each portion in greaseproof paper as you work

Place the butter in the fridge to chill and set. At this point, you can freeze the butter, ready to defrost as and when you need it