First, ignore the instructions about 'whisking' the water/milk into the powder. The whisk will quickly become jammed through and through with the lumpy product. Instead, put the two cups of water and half a cup of cream into a blender or food processor, add the powder, and blend for half a minute or so (the chocolate becomes thicker in the blender than the vanilla; the vanilla will nevertheless set correctly in the refrigerator).

Second, I agree that the chocolate is not quite as good as the vanilla. However, I add some drops of liquid Stevia which improves the taste. The vanilla does not need it, although I have used a few drops in it as well.

Finally, use good quality cream. I love Promised Land cream, if available in your area.