Preheat oven to 325 degrees.
Using an electric mixer, beat the butter and sugar together until combined.
Add the flour, water, salt, and baking powder to the bowl and mix with a hand mixer.
Add the milk slowly until the batter is sticky. Mix by hand with a wooden spoon.
Dust hands with flour. Transfer dough from bowl to a greased 9×9 pan. Gently flatten the dough in the pan.
Bake for approx. 1hr or until the edges of the johnnycake are browned. The johnnycake will not rise much.
Let cool for several minutes before cutting into the johnnycake.