1. In a large mixing bowl, combine all of the ingredients (except the 2 tablespoons cocoa/rye flour mixture at the end), stirring until the dough comes together. Knead until smooth, adding additional water or all-purpose flour 1 tablespoon at a time as needed. The dough should be soft and quite sticky. Cover and let the dough rise until puffy, about 1 1/2 hours.

  2. Lightly grease a long covered baker. Divide the dough in half. On a piece of greased parchment, pat one half into an 11" x 8" rectangle. Return the other half to the mixing bowl and add the cocoa/rye flour mixture to it. Knead until the dough is uniformly colored.

  3. Pat the colored dough into an 11" x 8" rectangle and place it on top of the first rectangle of dough. Starting at the long edge, roll the dough into a spiral, pinching the seam and rolling the log about 13" long.

  4. Place the dough in the prepared pan and add the cover. Let rise until puffy looking, about 1 1/2 hours. After 1 hour, preheat the oven to 400°F.

  5. Uncover the loaf, brush with the beaten egg, and give the top three diagonal slashes. Cover with the lid and bake for 15 minutes. Reduce the oven temperature to 350°F and bake for an additional 20 to 25 minutes. Uncover and bake for 5 minutes more, until golden brown and the center of the bread reads 200°F when measured with a digital thermometer.

  6. Remove the bread from the oven and turn it out of the pan onto a rack. Cool completely before slicing.