Preheat oven to 425F. Grease an 8-inch baking pan.
Mix cornmeal, flour, sugar, baking soda and salt. In a large bowl, whisk together butter, eggs and buttermilk. Stir buttermilk mixture into flour mixture (batter will be slightly lumpy).
Pour batter into baking pan.
Bake until a toothpick inserted in center comes out clean, 22 to 25 minutes.