Hey RR
Some of the members here recommended this for my Nookie on a couple different occasions. Unfortunately, he can't have anything raw, so won't work for us, but a few of the people here have had great success with these in regards to putting a bit of weight on!
This is the link to the recipe, they're called satin balls:
http://www.pets.ca/forum/showthread.php?t=53050
There are several different versions if you google "satin balls", but I can't say which is best because I haven't tried any of them
Hope it helps your little guy!