The cooking book can be found by Mystral Lake in Ashenvale. If you go southeast from the eastern end of Astranaar, you should run across the lake - there's a building on the northern edge of the lake - Retreat of some sort. A lady in there sells the cooking book. I don't know about where it would be for the Horde.
Another post in this forum asking the same question about cooking. Just tossing in a link to the other as well. Same information..
Other thread on expert cooking Edited, Tue Jan 4 00:27:36 2005 by Kiatrix