I actually went on a 1 day Indian Cooking Course last week, and they told me how they make the mint sauce and it's so simple.
Grab some yoghurt
Stir in a little sugar to the sweetness you desire, but let the sugar disolve properly in the yoghurt so that you don't get the crunch of the sugar
Add water to the yoghurt mixture to make it runny
then add a little mint sauce out of a jar
Finally and optional either add a small drop of green or yellow food colouring
It's done!! enjoy
I tried this at home after and it works well
