Firstly don't expect too much from kohat. Kohat has limited food options. If you are meat lover then Hujra restaurant KDA, Speen Ghar hungu phatak, average spicy biryani Student biryani near MCB Bank main bazar. Punjab restaurant on Indus Highway is good there Daal , white chicken karhai is good. Beef tikka in main bazar, dhoda chowk, University chowk