Heat the oven to 350 F. Put the butter or drippings in a 9-inch square baking pan or 10-inch iron skillet and place it in the oven. When the butter is melted and sizzling, carefully remove the pan or skillet to a rack.

Meanwhile, combine the cornmeal, flour, sugar, baking soda, and salt in a large mixing bowl; whisk to blend.

In a separate bowl, whisk 1 cup of milk with the buttermilk and eggs until smooth and well-blended.

With a whisk or electric mixer, combine the wet and dry ingredients to make a smooth batter.

Pour the batter into the prepared pan or skillet, then slowly pour the remaining 1 cup of milk over the batter.

Bake the custard-filled cornbread for 35 to 45 minutes, until the top is golden brown and the center is firm to the touch.