Johnnycakes are the New England equivalent of tortillas. The simplest recipes call for nothing but cornmeal, boiling water, and a little salt. The batter should be fairly thin so that when fried on a hot griddle, the batter is no more than a quarter of an inch thick. Rhode Islanders take their johnnycakes so seriously that they hold baking and eating contests every year. In Rhode Island, traditionally, the cake is made only from fine white corn that has been ground by a water process.
Whisk together cornmeal, salt and sugar (if used). Bring water to a boil and pour over the meal mixture, whisking to prevent lumps. Let the batter rest 10 minutes.
Butter a large skillet or griddle and bring it to about 375 degrees, just to a sizzle (do not burn the butter). Add enough milk (1/2 to a cup) to the batter to make it the consistency of mashed potatoes, and drop by spoonfuls to make cakes about 2 or 3 inches wide and several inches apart (they will spread).
Let the cakes gently sizzle on the grill for about 6 minutes or as long as 11 minutes until you bring them to a deep golden brown on the bottom and slightly firm on the top, before turning them over.
Add some more butter to the griddle, and/or place a thin pat of butter on each cake, before turning them over and cooking for another 6 minutes (or longer) until they are a deep golden brown color.