Preheat oven to 400°F. Add 1 tablespoon butter to cast iron skillet, and place in oven until butter melts. Remove pan from oven, and swirl butter to coat bottom and sides.
Add buttermilk, eggs, sugar, flour, cornmeal, salt, and baking powder to FourSide or WildSide jar in order listed. Secure lid and select "Batter."
Pour batter into hot skillet. Bake for 15–20 minutes or until wooden toothpick inserted in center comes out clean.
For double corn bread, prepare as written except fold ½ cup corn into batter after the "Batter" cycle ends.