The Collaborative International Dictionary of English v.0.48:

Hoecake \Hoe"cake`\, n.
   A cake of Indian meal, water, and salt, baked before the fire
   or in the ashes; -- so called because often cooked on a hoe.
   [Southern U.S.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

hoecake
    n 1: thin usually unleavened johnnycake made of cornmeal;
         originally baked on the blade of a hoe over an open fire
         (southern)