I use just less than a level scoop of mix a mousse & shake it up in the packet with the powder before adding it to 200ml of cold water and blitzing it with the hand blender for a minute. Then I tip it into two bowls. If you leave it to set for about 10 minutes it's kind of angel delight consistency and I normally eat the other one an hour or so later by which time it's set, but quite a soft set, a bit like a shop bought mousse. The vitamins don't deteriorate if you leave it more than 15 minutes, it's just the thickeners that can break down, but the mix a mousse seems to stop any change in texture or separation.