Mix the flour, cornmeal, sugar, baking powder and salt in a medium bowl, blending everything together with a fork or whisk. Add the milk, eggs, butter, water and vanilla extract to the bowl. Mix until everything is well combined, looking out for pockets of dry ingredients—a whisk is great for doing this.
Put a large nonstick skillet over medium-high heat and add enough oil to coat the bottom. When it’s hot, add the batter in 1/4-cup scoops. We got three in the pan per batch, using a 1/4 cup measuring cup and a small silicone spatula to dole out the batter.
Cook until brown on one side, about 2 minutes (bubbles will start to form on the edges). Carefully flip with a spatula and cook until done, about another 2 minutes or a little less. Transfer to a plate in a warming oven and continue cooking the johnnycakes in batches, adding more oil to the pan as needed.
Serve immediately with apple butter.