I've posted about this cart before, but I was just there recently and noticed a sign he has displayed that reads "Former chef at the Russian Tea Room". Can it be?
Anyway, his chicken on pita is the best in Midtown but a dollar more than from the grease carts all around. He also serves it with rice and salad, same goes for lamb on Pita or with rice and salad.
Give this guy a try, he's on the Southwest corner and the cart says Kwickmeal #5. He's there from lunch until 9 pm.