The cook is a great subskill for the "team mom" style PC who is the glue that holds the party together and the person who makes sure everyone is happy. It's like the cleric, but with more flavor than "heals you."
In the typical Five Man Band (Leader, Lancer, Smarty, Big Guy, and Softy), cooking falls to the Softy, and it's a great thing to do. Nothing perks up the spirits in a dark dungeon quite like a hot meal. A few of my games even had "food effects" that went into play if you rolled high enough (temp HP, attack/damage bonuses, etc.).