In a large bowl, stir together the yeast, water and molasses. Let stand for 5 minutes or until foamy. Beat in the all-purpose flour, milk powder and salt until smooth. Stir in the whole-wheat flour and cornmeal until a soft dough forms. Knead until smooth and elastic - about 4 minutes by hand or 2 minutes with an electric mixer. Transfer to a lightly greased large bowl, turn to coat with the grease, and cover loosely with plastic food wrap. Let rise in a warm, draft-free place for 45 minutes to 1 hour or until doubled in bulk.
Lightly grease a baking sheet. Punch down the dough, place it on a lightly floured surface, and knead lightly. Roll up to a 9"x13" rectangle with the long side facing you. Sprinkle the cranberries and walnuts over the dough and roll up, jelly-roll style. Place the loaf on the baking sheet, seam side down, and tuck under the ends. Cover loosely and let rise for 45 minutes to 1 hour or until doubled in bulk.
Preheat the oven to 375°. Bake for 30 minutes or until the loaf is brown and sound hollow when tapped on the bottom. Let cool on a wire rack. Makes 1 12" loaf.