The Cooking book for the Horde is in the Horde outpost (I can't remember the name) in Desolace. I've just reached cooking 200, and I don't know where to go next... but seeing as I'm only level 35, I still have 5 more levels to go before it matters.
____________________________
My
Mains over the years (dozens of alts not mentioned, and some games forgotten):
Celone Greenedge, Ranger, EQ (Retired)
Aerik, RDM/???, FFXI (Retired)
Jandu Balo, Scout/Surveyor, SWG (Retired)
Edifice Wrecks, Stone/Stone Tanker, CoH (Retired)
Dahlia, Lv. 60 Forsaken Mage, Lightning's Blade, WoW (Retired, Deleted)
Oleandra, Lv. 60 Forsaken Mage, Gurubashi PvP, WoW