Mix together the flour, sugar, salt, and yeast. Add mashed potatoes, warm water, oil, eggs, spices, minced onion, and flour. Knead 6-8 minutes. To one half, stir in enough of the remaining Bob’s Red Mill unbleached white flour to make a moderately stiff dough. Turn onto a lightly floured surface and knead until smooth and elastic, 5 to 8 minutes. Place in a well-greased bowl, turning once to grease the surface; set aside.
To remaining dough, stir in enough whole wheat flour to make a moderately stiff dough. Turn onto a lightly floured surface. Knead until smooth and elastic, 5 to 8 minutes. Place in a well-greased bowl, turning once to grease surface. Cover both doughs and let rise until double in bulk, about 1-1 ¼ hours. Punch down. Cover and let rest on lightly floured surface for 10 minutes. Roll out 1/3 of the light dough and 1/3 of the dark dough, each to a 12x8 inch rectangle.
Place dark atop light and roll up tightly, beginning at the short side. Repeat with remaining dough. Place in 3 greased 9x5 inch loaf pans. Cover and let rise until double in bulk, 45 to 60 minutes. Bake at 375° for 25 to 30 minutes or until done. Remove from pans and place on cool wire rack. Makes 3 loaves (12 slices each).
