Although it's not as awesome as "Iron Chef" you can earn a "Chef" title from achievements after Wrath of the Lich King launches. To earn the title, you need to complete all of the following cooking achievements:
- Grand Master cook
- The Cake Is Not A Lie
- Kickin' It Up a Notch
- The Northrend Gourmet
- Second That Emotion
- Critter Glitter
- Our Daily Bread (differs for horde and alliance)
- Dinner Impossible
- Captain Rumsey's Lager
- Sous Chef
- The Outland Gourmet
Read on for details on each achievement's criteria.
P.S. Collecting all the recipes in game is not required for the Chef title, but it is a related achievement. I've compiled a guide to all the recipes currently available in game and how to obtain them.