Preheat the oven to 425 degrees F. Brush a 9-by-13-inch baking dish with vegetable oil.
Whisk the cornmeal, flour, sugar, baking powder and salt in a large bowl. Stir in the eggs, milk and cup vegetable oil. Pour the batter into the prepared pan. Bake until a toothpick inserted into the center comes out clean, about 15 minutes. Cool completely. To use for stuffing, cut into cubes and let dry out overnight at room temperature.