In the bowl of an electric mixer fitted with the paddle attachment or in a 4-quart mixing bowl, stir together both flours, sugar (if using), salt, powdered milk and yeast. Add the butter, honey (if using) and water. Stir or mix on low speed until the ingredients form a ball. If some flour remains in the bottom of the bowl, very slowly add in more water. The dough should feel soft and supple.

Switch to the dough hook and knead at medium speed for about 6 minutes. Alternately, sprinkle a work surface with flour and knead for about 10 minutes, adding more flour if needed. The dough should be tacky but not sticky and register between 77º and 81ºF. Lightly oil a large bowl and transfer the dough to it, turning to coat the dough with oil. Cover with plastic wrap and allow to rise at room temperature for 1½-2 hours, until the dough has doubled in size.

Remove the dough and press it with your hands to form a rectangle about 5 inches wide and 6 to 8 inches long. Working from the short side, roll up the length of the dough one section at a time, pinching the crease after each turn.

The loaf will spread as you roll it, and the final length should be 8 or 9 inches, depending on the size loaf pan you have. Pinch the final seam closed, then roll the loaf back and forth to even it out, taking care not to taper the edges.

Place the loaf in a lightly oiled pan making sure that the ends of the loaf touch the ends of the pan. Mist the top of the loaf with spray oil and loosely cover with plastic wrap. Allow to rise for 90 minutes, or until the dough crests above the lip of the pan. Heat the oven to 350º and place a rack in the center. Place the bread pan on a baking sheet and bake for 25 minutes. Rotate the pan 180º and continue baking an additional 15-30 minutes, until golden brown on the top and sides. The finished loaf should be 190ºF in the center, and the bottom should sound hollow when thumped.

Remove the bread immediately from the pan and allow to cool on a wire rack for at least 1 hour, preferably 2, before slicing or serving. To store, wrap the cooled loaf in plastic wrap or store in a plastic bag in a cool, dark place. Do not refrigerate it because doing so will cause the bread to dry out.

If it cannot be eaten within 3 days, I recommend slicing then freezing it, which allows you to remove only as much as you need.