Place 1/2 cup water and cornmeal in a small saucepan. Bring to a boil over medium heat, stirring occasionally. Cook until mixture thickens; about 5 minutes. Remove from heat and stir in the butter or margarine and molasses. Let cool to lukewarm.
In a small mixing bowl, dissolve yeast in 1/2 cup warm water. Let sit until creamy; about 10 minutes.
In a large mixing bowl, combine the cooled cornmeal mixture with the yeast mixture; stir until well blended. Add 2 cups of the flour and the salt; mix well. Add the remaining flour, 1/2 cup at a time, stirring well after each addition. When the dough has pulled together, turn it out onto a lightly floured surface and knead until smooth and elastic, about 8 minutes.
Lightly oil a large mixing bowl, place the dough in the bowl and turn to coat with oil. Cover with a damp cloth and put in a warm place to rise until doubled in volume, about 1 hour.
Preheat oven to 375 degrees F (190 degrees C).
Deflate the dough and turn it out onto a lightly floured surface and form into a loaf. Place the loaf in a lightly greased 9x5 inch loaf pan. Cover with a damp cloth and let rise until doubled in volume, about 40 minutes.
Bake in preheated oven for about 30 minutes, or until the top is golden brown and the bottom of the loaf sounds hollow when tapped.
