In the body of a stand mixer fitted with the hook attachment, add 2 cups of the flour, dry milk, sugar, butter, yeast, and salt. Mix the ingredients around just to combine for a few turns.
Next, add the water to the bowl of the stand mixer and mix to combine.
On slow, add the remaining flour a little at a time until you come to 5 cups of flour (including the two you had already added). Increase the speed to medium-high, the dough should clean the sides of the bowl after a couple of minutes. If it doesn’t, add the remaining ½ cup flour a little at a time until the sides of the bowl are clean.
Continue to mix and knead the dough on medium-high speed with the dough hook for about 10 minutes. At this point the dough should be smooth and stretchy. Spray the dough with a little cooking spray, roll it around in the bowl until it is lightly coated. Cover the bowl with plastic wrap and let it rise in a warm place for about 1 hour.
Remove the plastic wrap and punch the dough down in the bowl, releasing the air bubbles.
Next, lightly flour a clean work surface. With your hands, knead the dough a few times to get any additional air bubbles out, this will take about 1 minute.
Spray 2 9x5-inch loaf pans with non-stick cooking spray.
Divide the dough into two even pieces. With your hands, roll them out into a log roughly the size of the pans. Place each log into a prepared baking pan.
Uncovered, let them rise until doubled in size, about 30-45 minutes.
At this point, preheat your oven to 400 degrees F.
Once doubled, make a slit down the center of the bread with a knife if desired. Place the loaves into the oven and lower the oven temperature to 350 degrees F. Bake for 30-35 minutes until golden brown.
Immediately brush the bread with the optional melted butter and let the bread cool in the pan for about 5 minutes.
Remove the bread from pans and cool on a wire rack completely.
Cut and serve as desired.