Preheat the oven to 400 degrees F and brush a 9-by-13-inch baking dish with vegetable oil.
Whisk the cornmeal, flour, sugar, baking powder and salt in a large bowl. In another bowl, whisk the egg, vegetable oil and buttermilk, then fold into the dry ingredients with a rubber spatula until just combined.
Transfer the batter to the prepared baking dish and bake until a toothpick inserted into the center comes out clean, 10 to 12 minutes. Transfer to a rack and let cool 15 minutes before serving.
Photograph by Alison Gootee
Courtesy of Food Network Magazine