Combine the cornmeal, sugar, salt, and baking soda in a large mixing bowl. Place the lard in an 8-inch heavy iron skillet, set in oven, and let melt. Meanwhile, mix the eggs lightly into the combined dry ingredients, then stir in just enough buttermilk to make a batter about the consistency of pancake batter.
Remove skillet from the oven, tilt so that lard greases both the sides and the bottom, and then pour the hot lard into the batter. Stir briskly just to mix.
Pour batter into the hot skillet and bake in hot oven until firm and lightly browned, about 25 minutes. Serve oven-hot, directly from skillet. The way to eat batter bread is to cut it into wedges as you would a cake, then to split each wedge horizontally and tuck in a lump or two of sweet butter while the bread is still hot enough to melt it.