Preheat oven to 425° F. Add oil to 9-inch cast-iron pan. Place in oven to heat for 5 to 6 minutes.
In a separate bowl, whisk milk and melted butter together. Add egg, whisk until incorporated.
Add wet ingredients to dry ingredients Cornbread mix, mixing only until all ingredients are incorporated.
Remove cast-iron pan from oven. Slowly pour in batter; smooth the top.
Bake for 25 to 30 minutes, or until the top is golden brown. Serve with butter.
Preheat oven to 425° F. Add oil to 9-inch cast-iron pan. Place in oven to heat for 5 to 6 minutes.
In a separate bowl, whisk milk and melted butter together. Add egg, whisk until incorporated.
Add wet ingredients to dry ingredients Cornbread mix, mixing only until all ingredients are incorporated.
Remove cast-iron pan from oven. Slowly pour in batter; smooth the top.
Bake for 25 to 30 minutes, or until the top is golden brown. Serve with butter.