In 3-quart saucepan, heat stock to lukewarm. remove from heat. Add cheese, oil, honey, thyme and dill. Gently stir in yeast. Stir in mashed potatoes. Set aside 10 minutes to proof (yeast will become foamy).
In large bowl, mix whole wheat flour and unbleached flour. Gradually stir 4 cups flour into potato mixture.
Turn dough onto floured surface and knead in remaining flour. Knead about 10 minutes, or until dough is smooth and elastic.
Lightly oil large bowl. Add dough and turn to coat all sides. allow to rise in warm, draft-free place 30 to 40 minutes, or until doubled in bulk.
Punch down dough and knead 1 minute. Divide into two portions and form into loaves.
Coat two 8 1/2 x 4 1/2-inch loaf pans with nonstick spray. Add dough, cover, and let rise 30 minutes, or until doubled in bulk. Bake at 350° 30 to 35 minutes, or until loaves sound hollow when tapped. Allow loaves to cool on wire racks 30 minutes. Makes 2 loaves.