In a large bowl, dissolve yeast in warm water. Add the buttermilk, butter, sugar, salt, baking soda and egg. Beat until blended. Stir in enough flour to form a soft dough. , Turn onto a floured surface; knead until smooth and elastic, 6-8 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 1 hour. , Punch dough down. Turn onto a lightly floured surface; knead for 5 minutes. Divide into 24 pieces. Shape each into a ball. Grease a 12-in. cast-iron or other ovenproof skillet and sprinkle with cornmeal. Place rolls in prepared pan. Cover and let rise until doubled, about 40 minutes. , Drizzle butter over rolls. Bake at 375° until golden brown, 18-20 minutes. Remove from skillet to a wire rack to cool.