Preheat oven to 375°F and grease an 8” square pan. Melt butter in large frying pan. Remove from heat and stir in sugar. Quickly add eggs and whisk until well blended. Combine buttermilk with baking soda and stir into mixture in the frying pan. Mix cornmeal, flour and salt together, then add to the pan. Stir until well blended but a few lumps remain. Pour batter into the prepared baking pan. Bake for 30-40 minutes, or until a toothpick inserted in the centre comes out clean.