When I first did them they were lumpy but after a bit of experimenting I find the best way is to use a spoon and mix the mousse powder and the shake powder together in a dry cup/pot(if there is a bit of wet it starts to set!). Then put the water in my shaker cup, tip in the mixed powder and shake together like you would to make a shake. Then pour it into a bowl to set in the fridge. I have been using a bit more water and a bit more mousse powder to make a bigger portion though because its so nice! :-D x