In another bowl, beat the milk, melted butter, egg, vanilla, and food coloring until blended. Pour the wet ingredients into the dry ingredients and beat until just blended (it's better to leave a few lumps than to overmix and make tough hotcakes). The hotcakes will be lighter if you let this batter stand at room temperature for about 30 minutes, or refrigerate it up to 1 day.
2) Heat a griddle or large heavy pan (cast iron is perfect) over medium heat. The griddle is hot enough when a drop of water skitters quickly across the surface. Brush the griddle with a little melted butter. Pour about 1/3 cup of batter for each hotcake, leaving a little space between the hotcakes to make it easy to turn them. Cook them until golden brown underneath (lift a corner to peek) and bubbles start to pop on the topsides. Flip the hotcakes carefully and cook them until the undersides are golden brown. Repeat with the rest of the batter. Serve hot with butter and maple syrup.