Remember to use very cold water! It works better!
I measure out my water and put the jug in the fridge for about an hour. Then mix the two powders together and add the powder to the water, not the other way around. Mix for at least a minute - the mixture goes thicker - pour into a dish and put in the fridge for about 10 mins.
Tesco sell a hand blender for about £3 - it is worth it - honestly!