Put the warm milk in your mixer bowl and sprinkle the yeast and sugar over it. Mix together and let sit for 5 minutes to make sure the yeast activates and gets foamy.
Add the water, whole wheat flour, 3 cups of the bread flour, shortening, honey, and salt.
Let the mixer knead on low speed for 2 minutes with the dough hook attachment, scraping down as needed. Add small amounts of bread flour, up to another half a cup, until the dough is the right consistency, (you want a soft dough that is easy to work with, but you want it to feel tacky, but not stick to your fingers. You do NOT need to use the whole additional amount.) Continue to let the mixer knead for another 2 minutes when it is the right consistency.
Scrape the dough in to a ball in your bowl, cover the bowl with plastic wrap and a clean towel and set in a warm place to rise for 1 hour or until it has doubled in size. (I turn the oven on at the lowest temperature for just 1 minute, then turn it off and put the mixing bowl in there.)
Turn the dough out on to a lightly floured pastry mat or counter, and knead for a minute, then divide the dough in two equal portions.
Roll out each piece of dough just slightly then fold over in thirds, (pressing together with the heel of your hand), tuck in the ends, and place the bread with seams down in two lightly greased 9×5 bread pans.
Cover the pans lightly with plastic wrap and let the loaves rise another 30 minutes.
When ready to bake, preheat oven to 350.
Remove plastic wrap, brush the loaves gently with egg wash, then bake the loaves at 350 for about 30 minutes. (Bread should register 190 degrees with an instant read thermometer to be fully baked, but not overbaked.
Optional: gently brush some melted butter on the top of each loaf as soon as it comes out for a softer crust.
Remove from the oven and let cool 10 minutes before popping the loaves out of the pans on to a cooling rack.
Bread should cool for a minimum of 30 minutes before slicing!