johnnycake vs johnny cake

johnnycake and johnny cake both are nouns.

Word	Noun	Adjective	Verb	Adverb
johnnycake	Yes	No	No	No
johnny cake	Yes	No	No	No

As nouns, johnnycake and johnny cake are synonyms defined as:

johnnycake and johnny cake: cornbread usually cooked pancake-style on a griddle (chiefly New England)

Other synonyms of johnnycake include journey cake.

johnnycake (noun)	johnny cake (noun)
cornbread usually cooked pancake-style on a griddle (chiefly New England)	cornbread usually cooked pancake-style on a griddle (chiefly New England)