1 ¼cupsmilk,buttermilk (see recipe intro), or plain yogurt
Preheat the oven to 375°F.
Put the butter in a medium-size ovenproof skillet (preferably cast-iron) or an 8-inch-square or round baking pan and place it in the oven to heat until the pan is hot and the butter is melted, about 4 minutes.
Meanwhile, combine the cornmeal, flour, baking powder, salt, and sugar in a large bowl. In a smaller bowl, mix the egg and milk together. Pour the melted butter from the pan into the egg and milk mixture and whisk to combine (but don’t wipe out the excess melted butter in the pan).
Stir the milk mixture into the dry ingredients, stirring just until they are barely combined. Scrape the batter into the pan that you used to melt the butter, and spread it evenly.
Bake the cornbread until the top is lightly browned and a toothpick inserted into the center comes out clean, about 25 minutes. Place the skillet on a wire rack to cool for at least 10 minutes. Serve the cornbread hot, warm, or at room temperature.