Both Horde and Alliance become artisan cooks by completing the quest Clamlette Surprise, obtained at level 35+ with 225 cooking skill.
The quest is given by Dirge Quikcleave at the Gadgetzan inn. To complete the quest you have to give him 20x 
[Alterac Swiss], 10x 
[Zesty Clam Meat], and 12x Giant Eggs. Quest rewards are Artisan Cooking skill, and 20x 
[Clamlette Surprise].
Tips
Alterac Swiss can be purchased from vendors in some cities. For Alliance, it can be be purchased at the cheese shop in Stormwind, and in Southshore, from Inn Keeper Anderson. The Horde can purchase Alterac Swiss from the innkeeper in Thousand Needles.
This quest is often completed by purchasing the required items off auction.
- See also