"Now I Am the Master" is add to Cooking achievement in MOP: Obtain the Cooking School Bell, Take on an apprentice in the arts of cooking, and teach your student to become an expert.
You cannot purchase it until you have completed the quest "To Be a Master" from Sungshin Ironpaw which involves cooking all level 600 meals from all six cooking specializations. You can purchase Cooking School Bell at Halfhill Market for 50 Ironpaw Tokens. Using the bell will summon Nomi, who will have a daily quest that will raise his cooking skill. You will award the achievement after completing five lessons and becoming Best Friend with Nomi. To express his thanks, Nomi will offer a daily "A Token of Appreciation" every day to allow you to get Goodies from Nomi and one Ironpaw Token. You can gain five food randomly when opened Goodies from Nomi.
Ironpaw Token can obtain by completing a daily quest, also can be purchased from Spirit of Harmony Vendor with Spirit of Harmony. If you don't want to do dailies, then the one Ironpaw Token that Nomi offers every day will help you buy cooking materials, toys and Cooking set.
It is happy to enjoy the food provided by the apprentice, isn't it?