I soak Eukanuba puppy food for several hours until it is completely soft then I warm it, add yogurt and mash it until it is basically the consistency of oatmeal.
Kibble soaked in warm water and goat's milk! When first starting on gruel, I run it through the blender until it is a medium-thick-soupy consistency. As they get older, mash it with a fork until it becomes more like the oatmeal consistency.