Add the lukewarm water and yeast to the bowl of your mixer, stir and let it dissolve for 5 to 10 minutes.
To the yeast mixture, add the molasses, cocoa powder, salt, caraway seeds, vegetable oil, rye flour, and about 2 1/2 cups of all purpose flour. Beat on medium speed until smooth. Add in remaining flour and keep mixing until it forms a firm dough (about 5 minutes), the dough should come clean from the side of the bowl.
Spray a large bowl with cooking spray and place the dough in the bowl, spray the dough as well with cooking spray, cover with a clean damp kitchen towel or plastic wrap and let the dough rest until it doubles in size in a warm, draft free environment.
Place a piece of parchment paper on your work surface. Sprinkle the cornmeal over the parchment paper. Punch down the dough and stretch it from the center to form a ball. Place the ball onto the prepared parchment paper. Let it rise for another 30 to 40 minutes until doubled in size. Once doubled, sprinkle a bit of flour over the top of the dough and cut a few slashes with a sharp knife.
Preheat the oven to 425℉. Place a shallow pan (not glass) on the lower rack in the oven. Transfer the bread with the parchment paper on a baking sheet or into a Dutch oven and place in the oven. Pour 1 cup of water in the shallow pan on the lower rack.
Bake for 30 minutes until crusty and golden brown