In the current state of the Cooking profession, it is necessary to take up Fishing in order to progress one's skill to the maximum level. For some unknown reason, Cooking recipes between 275 and 285 skill have been changed in the recent patches. As community MVP Highlander points out, all but one of the recipes that grant skill-ups in this range require materials that can only be gained through fishing (which, I suppose, can also be purchased off of the auction house). The only recipe that doesn't require fishing is only attained through running Dire Maul, which seems to be an unrealistic requirement.
While not offering any explanation as to why these recipes were ever changed in the first place, Blizzard poster Salthem gives hope of a solution. New recipes are set to be added in patch 2.4 which should hopefully fix this problem. While not providing a lot of details, he does mention that the recipes will definitely bridge this gap.
Only time will tell exactly what recipes are being added, but perhaps they'll add a few more reliable ways to acquire skill points between 350 and 375 as well. What type of cooking recipes would you like to see in the patch?