Set the oven to 350F (do this toward the end of the second rise)
Put the cornmeal, salt, butter, and molasses in the bowl of a stand mixer fitted with the paddle attachment. Add the boiling water and mix to blend. Let sit for about 15 minutes until it is lukewarm to the touch.
Mix in the flours, dry milk, and the yeast until all the flour is incorporated, then cover with plastic and let sit for 20 minutes.
Change to the dough hook, and knead the dough for about 7 minutes on the medium speed of your stand mixer, until it is smooth.
Lightly oil the top of the dough, and cover. Set in a warm place for about an hour, to double in bulk.
Remove the dough to a floured board and divide in half. Then take each half and divide into three equal parts. Take each piece and form it into a smooth round.
Place the rolls in a lightly buttered cast iron skillet, with one in the center and the rest around it. Cover and let the rolls rise in a warm place for 90 minutes. Toward the end of this time, preheat the oven.
Bake the rolls for about 35 minutes until risen and golden.
Just after you remove the rolls from the oven, brush the tops with a little melted butter.