Combine the yeast, sugar, and 1/4 cup of the warm water in the mixer bowl or in a large mixing bowl and mix well. Set aside for about 10 minutes, while the yeast "blooms." When the yeast looks frothy, add the melted butter, molasses salt, flour, and cornmeal. Slowly add up to 1 cup more warm water, mixing with the dough hook or a wooden spoon. The amount of liquid may vary, depending on the flour, so add just enough water to form a soft, but not sticky dough. Knead by machine for about 10 minutes, or by hand for about 15 minutes, until the dough is smooth and elastic.
Lightly oil or butter a large bowl. Shape the dough into a ball, place it in the bowl, and turn it once so it is lightly greased all over. Cover with plastic wrap or a damp cloth and place in a warm, draft-free spot. (An oven that has been heated to 200 degrees and then turned off is a perfect spot). Let the dough rise until doubled in volume, about 1 hour.
Grease 2 (9 1/2 by 5-inch) loaf pans. Turn the dough out onto a lightly floured surface. Cut it in 1/2 and shape each 1/2 into a loaf. Place each in the greased loaf pans, return to the warm spot, and let the loaves rise until they are about doubled in size, 20 to 30 minutes.
Meanwhile, preheat the oven to 350 degrees. Brush the top of the loaves with the egg wash and bake for 1 hour, or until deep golden brown. To test for doneness, remove the hot bread from 1 pan and knock on the bottom of the loaf: you will hear a hollow sound if the bread is done. If necessary, return to the oven for 5 to 10 minutes. Turn both loaves out of the pans and cool on a rack for at least 20 minutes.