Dissolve active dry yeast in warm water in a large mixing bowl.

Stir in molasses, caraway seeds, salt, vegetable shortening, rye flour, 1/4 cup cornmeal, and cocoa.

Beat the mixture at medium speed with an electric mixer until smooth.

Gradually stir in enough all-purpose flour to make a stiff dough.

Turn the dough out onto a lightly floured surface.

Cover the dough and let it rest for 10 to 15 minutes.

Knead the dough until it becomes smooth and elastic, approximately 5 to 10 minutes.

Shape the dough into a ball and place it in a well-greased bowl, turning to coat the top with grease.

Cover the bowl and let the dough rise in a warm, draft-free place (around 85 degrees Fahrenheit) for 1 hour or until it has doubled in bulk.

Punch the dough down to release air, then shape it into a ball again.

Cover the dough and let it rise in a warm, draft-free place for about 40 minutes or until it has doubled in bulk.

Grease a baking sheet and sprinkle it with cornmeal.

Punch the dough down again and divide it in half.

Shape each half into a round, slightly flattened loaf.

Place the loaves on opposite corners of the prepared baking sheet.

Cover the loaves and let them rise in a warm, draft-free place for 1 hour.

Bake in a preheated oven at 375 degrees Fahrenheit (190 degrees Celsius) for 25 to 30 minutes, or until the loaves sound hollow when tapped.

Remove the baked loaves from the baking sheet and let them cool completely on wire racks.