Cook potato in boiling water 10 minutes or until very tender.
Drain potato in a colander over a bowl, reserving 1 cup cooking liquid. Mash potato with a fork until smooth. Cool cooking liquid to 100 to 11
Dissolve yeast and sugar in cooled cooking liquid in a large bowl; let stand 5 minutes. Lightly spoon flour into dry measuring cups; level with a knife.
Add 2 1/2 cups flour, mashed potato, 3/4 cup shredded cheese, oil, salt, mustard, and pepper to yeast mixture; stir until well-blended.
Turn dough out onto a floured surface. Knead until smooth and elastic (about 10 minutes); add 1/2 cup flour, 1 tablespoon at a time, to prevent dough from sticking to hands (dough will feel tacky).
Place dough in a large bowl coated with cooking spray, turning to coat top. Cover dough, and let rise in a warm place (85), free from drafts, 45 minutes or until doubled in size. (Press two fingers into dough. If indentation remains, the dough has risen enough.) Punch dough down; sprinkle with 1/2 cup diced cheese. Knead dough until cheese is well-blended (about 5 minutes), and add enough of remaining flour, 1 tablespoon at a time, to prevent the dough from sticking to hands.
Roll into a 14 x 7-inch rectangle on a lightly floured surface.
Roll up the rectangle tightly, starting with a short edge, pressing firmly to eliminate air pockets, and pinch seam and ends to seal.
Place roll, seam side down, in a 9 x 5-inch loaf pan coated with cooking spray. Cover and let rise 40 minutes or until doubled in size.
Preheat oven to 37
Uncover dough.
Bake at 375 for 55 minutes or until loaf is browned on the top and sounds hollow when tapped.
