I'm still working on my Chef's Hat, and there was always one cooking daily which took more time than the others: Mustard Dogs. The wild mustard is easy enough to find in the grassy areas of Dalaran, but the Rhino Meat always used to give me fits. I would fly out to Sholazar Basin and kill rhinos until I was bored which was usually right at the 4 meat mark. After whining about it in Twitter one day, multiple people replied to me with their suggestions for rhino hunting grounds, with the consensus being Borean Tundra.
The section of Borean Tundra in between Amber Ledge and Warsong Hold is home to roaming Rhino families. If you AoE just some of the members of a family, the rest of the family will aggro. So, if you are of sufficient level and have a good Area of Effect or cone attack, you can take down multiple families of rhinos in a very short time -- even if there is someone else there farming rhinos, too. The hard part then becomes making sure you've looted each corpse in a pile of enormous dead mammals. Now, if I'm out of Rhino Dogs, I just take a few minutes to go stock up and then take a dragon back to Dalaran, just because I can.
Where do you get the meat you need to make the recipes you use regularly? Perhaps you know of where large families of Shoveltusks graze? Do you have any other tips for budding chefs looking to speed up their meat farming?