You may not have made it all the way to 350 during the holiday -- if you need to nab a few other points, you'll have to head to Outland and level up there for a little bit. Talbuk Steak is a good one to do if you need that extra boost -- it's vendor purchased, easily farmable (or buyable on the AH), and the Stam boost isn't bad. Once you've hit 350, then you'll need to head to Northrend. You can train at the cooking trainers in the faction inns in Dalaran. You'll probably also want to stop off and pick up the Northern Cooking quest, as Northern Stew will help you get relatively easily to 375. After that, it's time for the booze.