1. Combine the water, molasses, milk, butter, caraway seeds, salt, espresso powder, and ground fennel seeds in a small pot and bring to a boil over medium heat. Whisk in the cornmeal and remove the pot from the heat. Add the chocolate and stir until melted. Allow the mixture to cool until tepid, about 10 minutes.
2. Combine the warm water, yeast, and sugar in the bowl of a standing mixer fitted with the dough hook. Let the mixture sit until it becomes bubbly or creamy, about 5 minutes. Add the three flours and the cornmeal mixture. Mix on low speed until combined. Continue to mix for 10 minutes, scraping the hook about halfway through.
3. Transfer the dough to a lightly floured work surface, knead it several times with lightly floured hands, and form it into a ball. Lightly oil a medium mixing bowl, and add the dough, turning it once to oil the top. Cover the bowl with a kitchen towel and set it in a warm, draft-free place until the dough has increased by half, 2 to 3 hours.
4. Remove the dough from the bowl, knead it several times with lightly floured hands, and form it into a ball. Set it on a parchment-lined baking sheet, cover it with a kitchen
towel, and set it aside to rise a second time, 1 to 1 1/2 hours. Once it has increased by half, the dough is ready to bake.
5. Position an oven rack in the top third of the oven, and preheat the oven to 350°F. Fill a small spray bottle with water.
6. Right before baking, use a serrated knife to slash an X in the top of the dough. Spray water all over the dough. Bake for 1 hour and 5 minutes, spraying the dough several
times during the first 10 minutes, and rotating the baking sheet halfway through baking. The bread is done when it registers an internal temperature of 200°F on an instant-read thermometer inserted through the bottom. Transfer the bread to a wire rack to cool.
7. The cooled bread can be wrapped in plastic wrap and stored overnight at room temperature or frozen for up to 3 months.
Note: Blackstrap molasses is a dark, less sweet, but strong-flavored molasses. If you need a substitute, try barley malt syrup or robust molasses. Though there may be a slight difference in color and flavor, the bread will still be delicious.
Yield: 1 round loaf