Potato Bread - makes 4 loaves

4 cups whole-wheat flour
Vegetable oil spray
4 cups all-purpose flour
2 tbsp active dry yeast, 2 envelopes
2 tbsp hohey
2 1/2 tsp salt
1 1/2 cups mashed potatoes
1 1/2 cups skim milk
1/4 cup margarine
1/2 cup water
4 large egg whites

Glaze
1/4 cup skim milk

Grease two large baking sheets and one large bowl with vegetable oil spray, set aside.
In another large bowl, combine whole-wheat and all-purpose flours. In another large bowl, mix together yeast, honey, salt and 1 1/2 cups of combined flour.
In a 2-quart saucepan, combine mashed potatoes, milk, margarine and water. Heat over medium-high heat until very warm, 120-130 F, stirring. The margarine does not need to melt completely.
With electric mixer at low speed, beat liquid ingredients into dry ingredients. Add egg whites, increase mixer speed to medium and beat 2 minutes, scraping bowl occasionally.
Beat in 1 cup flour to make a thick batter; beat 2 minutes longer.
Stir in 3 more cups of flour. Turn the dough onto a well-floured board. Knead in as much of the remaining 2 1/2 cups of flour as necessary to make a soft, but not sticky, dough. Knead the dough for 10 minutes, or until smooth and elastic. Shape into a ball and place in the greased bowl, turning to coat all sides.
Cover the bowl with a clean towel and set in a warm, draft-free place to rise, about 1 1/2 hours, or until doubled in bulk.
Turn the dough onto a lightly floured surface, punch down and knead out the large air bubbles. Divide the dough into four equal pieces.
Shape each piece into an oval, about 10 inches long. Cut two parallel slashes on top of each loaf, place on the greased baking sheet (two loaves per sheet) and cover with a clean towel. Allow to rise in a warm, draft-free place for 1 hour, or until doubled in bulk.
Preheat oven to 350 F. Brush each loaf with skim milk. Bake 35-45 minutes, or until loaves are golden brown and sound hollow when tapped.
Serve warm or at room temperature.