In the bowl of a stand mixer, combine the yeast, sugar, and water. Allow the yeast to bloom for five minutes. If the mixture does not bubble and foam after five minutes, discard and begin again with fresh yeast.
Add the butter, brown sugar, eggs, pumpkin, pumpkin spice blend, cranberries, seeds and walnuts to the mixing bowl. Blend the mixture together with the dough hook attachment of your stand mixer.
Once the mixture is blended, add the whole wheat flour and salt. Mix to form a thick batter. Slowly add the all-purpose flour to the batter. Continue mixing, and adding the remaining flour, until the dough holds together and pulls away from the sides of the mixing bowl. The dough should feel pliable; too stiff or dry.
Turn the dough onto a floured countertop and knead it for 4-5 minutes. Stop kneading; allow the dough to rest while you clean your bowl and oil it with a small amount (1 tsp) of vegetable oil. Continue kneading the dough for another 5 minutes or until the dough is smooth, elastic, and no longer sticky.
Place the dough into the greased bowl and turn it over once to coat its surface with oil. Cover the bowl with plastic film and a clean kitchen towel and allow it to rise in a warm, draft-free area of the kitchen for 1-1 1/2 hours, or until doubled in bulk.
Punch the dough down to expel the gases. If you prefer a dough with a finer crumb, allow the dough to rise a second time for an additional hour.
Once the dough has finished its rise, punch it down a final time and divide the dough into two equal pieces. Shape the dough into loaves and put them into greased loaf pans. Allow the dough to rise one final time for 1 hour, or until the dough reaches the tops of the pans.
While your loaves are rising, preheat your oven to 400°F. Place the loaf pans into the oven and reduce the heat to 350°F. Bake the loaves for 30-35 minutes, or until the loaves sound hollow when tapped.
Allow the loaves to cool for five minutes before removing them from the pan and cooling until warm-they slice best when warm. You may also wrap the loaves in plastic film and freeze for up to two months before enjoying.