4 cups rye flour 2 cups whole bran cereal 2 envelopes dry yeast 2 tablespoons caraway seeds, crushed 2 teaspoons instant coffee 2 teaspoons salt 2 1/2 to 3 cups unbleached all-purpose flour 1 teaspoon granulated sugar 1/2 teaspoon fennel seeds, crushed 2 1/2 cups water 1/4 cup (1/2 stick) butter 1/4 cup white vinegar 1/4 cup dark molasses 1 (1 ounce square) unsweetened chocolate 1/2 cup water 1 teaspoon cornstarch
Lightly grease a large bowl and two 8-inch layer cake pans; set aside.
Combine first 8 ingredients in mixing bowl.
Combine 2 1/2 cups water, butter, vinegar, molasses and chocolate in 2-quart saucepan. Place over medium heat and cook, stirring frequently, until chocolate is almost melted but mixture is still lukewarm. Turn into mixing bowl and begin beating. Gradually add flour, 1/2 cup at a time, to make a soft dough and beat about 3 minutes. Turn dough onto lightly floured board. Cover with bowl and allow dough to rest 10 to 15 minutes.
Knead dough until smooth and elastic, about 10 to 15 minutes, adding additional flour as needed. Place in greased bowl, turning to coat entire surface. Cover with plastic wrap and hot, damp towel and leave in warm place until doubled in volume.
Punch dough down and turn onto lightly floured board. Shape into 2 balls and place in prepared pans. Cover with plastic wrap and leave in warm place until doubled.
Preheat oven to 350 degrees F. Bake breads 40 minutes.
Combine water and cornstarch in saucepan and bring to boil over high heat; boil 1 minute. Brush lightly over bread and return bread to oven for about 5 minutes, or until tops are glazed and loaves sound hollow when tapped. Remove from pans and allow to cool on racks.