This is a successful recipe! It is from Nourishing Traditions by Sally Fallon. I used Yeo Valley Natural Yoghurt, and produced cream cheese, (which tastes a bit like Philadelphia, but better) and whey which is useful in loads of recipes.
You need to set up a bowl with a sieve on top, (I used a plastic one have read this is better when making kefir), and line it with muslin or cheesecloth. Then just take some yoghurt, (about 250g is a good amount, you can use more), put it on top of the fabric, and put a plate on top. Wait several hours, until the whey and yoghurt cheese separate, then tie up the cloth and hang over the bowl using a wooden spoon until the whey stops dripping. Then put in jars in the fridge. The yoghurt cheese should last about a month, and the whey about 6 months. Brilliant!
This can also be made with raw milk, pimma milk or buttermilk, see http://thenourishingcook.com/1-whey-cool/#more-37.
I tried it with raw milk, I thought it was ok, but my husband said it tasted like gone off milk and wouldn’t eat it!
Give it a go, I really recommend this recipe!