Whisk together buttermilk, eggs, sugar, and baking soda in a large bowl; stir in corn. Stir together cornmeal and flour; gradually whisk flour mixture into buttermilk mixture.
Whisk in melted butter.
Pour batter into a buttered 10-inch cast-iron skillet.
Bake at 350 for 35 minutes or until a wooden pick inserted in center comes out clean.
Remove from pan, and cool completely on a wire rack (about 1 hour).
