Preheat the oven to 375°F. Lightly grease your 9" skillet with cooking spray or extra melted butter.
In a medium bowl, whisk together the flour, cornmeal, sugar, baking powder, baking soda, and salt.
In a small bowl, whisk together the milk, melted butter, vegetable oil, and egg.
Pour the wet ingredients all at once into the dry, and stir quickly but gently just until everything is combined. Make sure you don't over mix! You don't want tough dense cornbread.
Spread the batter into your prepared skillet, and bake for 20-25 minutes, just until the edges begin to pull away from the side, and a toothpick comes out clean.
Remove from the oven and cool on a rack for ~5 minutes before cutting. Serve immediately. Leftovers will keep for a few days well wrapped at room temp.
Enjoy!