This is an old family recipe that just got written down with measurements in 2013. I watched my mother make it many times and she always said she didn't know how much of anything - "she just eye balled it". I sat in the kitchen one day and measured the ingredients, but we still played with the milk so you will have to also!
Preheat oven to 400. Pour oil in 10-12 " iron skillet and let skillet preheat in oven. Your cornbread mixture should sizzle when you pour into pan. This helps it get a good crunchy crust on the outside.
Mix corn meal and flour together in a mixing bowl. Add the egg and a little milk. The measurement on milk is about 1/2 cup, but you have to add a little at a time until the mixed consistency is like a brownie recipe. When you pour it into the pan it should slowly fill the pan, you don't want it to be to thin.
Bake at 400 until golden brown - about 20 minutes.