2 1/4 teaspoons active dry yeast
3/4 teaspoon sugar
2 cups dark rye flour
2 cups all-purpose flour, divided
3 3/4 teaspoons caraway seeds, crushed
1 teaspoon finely ground coffee beans
1 teaspoon onion powder
1 teaspoon salt
1/4 teaspoon fennel seeds, crushed
2 tablespoons white vinegar
2 tablespoons dark molasses
1/2 ounce unsweetened chocolate
2 tablespoons margarine
 vegetable oil, for greasing bowl and pan
1/2 teaspoon cornstarch

Stir together yeast, sugar, and 1/4 cup warm water in bowl. Let stand ten minutes.

Whisk together rye flour, 1/2 cup all-purpose flour, caraway seeds, coffee, onion powder, salt, and fennel seeds in bowl.

Combine 1 cup water, vinegar, molasses, chocolate, and margarine in saucepan, and heat over low heat until margarine and chocolate are melted.

Stir molasses mixture into rye flour mixture. Add yeast mixture, and stir with wooden spoon for two minutes. Add remaining all-purpose flour 1/2 cup at a time, until soft dough forms. Transfer to floured work surface. Let rest 15 minutes.

Knead 15 minutes. Place dough in bowl coated with vegetable oil. Let rise one hour, or until doubled in size.

Preheat oven to 350 degrees. Coat baking sheet with oil. Shape dough into ball, and place on prepared baking sheet. Bake 50 minutes, or until bread sounds hollow when tapped.

Bring cornstarch and 1/4 cup water to a boil in saucepan. Cook one minute, stirring constantly. Brush cornstarch mixture over top of loaf. Bake two to three minutes more. Cool on wire rack.