American evidence forjohnnycakeis somewhat earlier than that forjourney cakewhich has often been suggested as the source of this word. Other suggested sources are the nameJohnnyandjonakina thin wafer(see Dictionary of Americanisms), perhaps of Indian origin.
1826  (1832)  Indian meal is also sometimes made into cakes, which are called Johnny cakes. . . .
1942  "Think of all the johnny-cake we'll grow on that patch." "You'll be planting corn, then."
1964  . . . Johnny cake [was made] except in those ultra-loyal sections where an American dish was considered disloyal.
2n.Obs. a similar cake made of wheat flour.
1852  First, I want you to lend me ten pounds of flour to make some Johnnie cakes.
1887  (1962)  Some of the wheat we took turns grinding in the coffee mill for porridge, sifting some for johnny cake, as the corn meal is all used.