2 tablespoons unsalted butter, melted, plus more for greasing the pan
1 cup yellow cornmeal, preferably stone-ground
1 cup unbleached all-purpose flour
2 teaspoons baking powder
1/2 teaspoon baking soda
4 teaspoons sugar
1/2 teaspoon salt
2 eggs
2/3 cup buttermilk
2/3 cup milk

In a large bowl, whisk the cornmeal and next five ingredients together.
Push the dry ingredients up the sides of the bowl to make a well. Crack
the eggs into the well and stir lightly; add buttermilk and milk. Stir all
quickly until almost combined. Add melted butter and stir until the
ingredients are just combined. Pour the batter into a greased 9-inch
square baking pan. Bake at 425 degrees until the top of the cornbread is
golden brown and lightly cracked and the edges have pulled away from the
sides of the pan, about 25 minutes. Transfer the pan to a wire rack to
cool slightly, 5 to 10 minutes. Cut cornbread into squares and serve warm.