How to Make It
Preheat the oven to 375°. Put two 8-inch cast-iron skillets or round cake pans in the oven to heat up. In a large bowl, whisk the cornmeal with the flour, sugar, baking powder and salt. In a medium bowl, whisk the oil with the eggs and milk. Using a flexible spatula, gently fold the wet ingredients into the dry ingredients until just blended; do not overmix.
In each hot skillet, melt 1 tablespoon of the butter, swirling to coat the bottoms and sides. Divide the batter between the skillets and shake to smooth the tops. Bake in the center of the oven for 35 minutes, until springy when lightly pressed in the center. Transfer the corn breads in the pans to racks to cool. Turn them out onto a baking sheet. Cover with plastic wrap and keep at room temperature overnight.