Combine the cornmeal, flour, sugar, salt, baking soda, and baking powder in a bowl., stir or whisk.
Gently stir in sourdough starter.
Either refrigerate 8-12 hours to allow fermentation (then proceed to next step)
If baking immediately,add in eggs, milk, and oil.
Gently whisk until smooth.
When ready to bake, preheat oven to 375 degrees.
Place the 2 tb butter skillet, then place skillet in the oven as it preheats.
Remove hot skillet from oven then pour in the batter immediately.
Place pan back into the oven and bake for about 25 minutes, or until golden brown and the edges pulled away from the sides of the pan.