This is an absolute favourite of mine and indeed the household. I make it with biodynamic wholemilk natural yoghurt and sometimes make it with limes instead of lemons. We have a profusion of oranges here at the moment so a new version may be tried on the weekend.
The recipe is here.
It looks like this:
Until you go to the bathroom and your 21 month old toddler gets into it. Then it looks like this: