Preheat oven to the lowest temp it will allow. Mine is 170 degrees. Turn oven off.
In a bowl heat milk to just slightly above room temperature (I heat mine in a glass measuring cup in the microwave for about 1 minute 15 seconds).
Into the warm milk, add the yeast and white sugar. Stir until dissolved. Allow the yeast mixture to proof (bubbles or foams) for 5-10 minutes.
In your mixing bowl combine the flour, potatoes, yeast mixture, butter, and salt.
Mix for 5-10 minutes with the dough hook if you own a stand mixer, or hand beat until and knead until the is a thoroughly combined and is a bit elastic.
Split the dough into halves and form roughly into the shape of your loaf pans. Place each half into a greased loaf pan (e.g. cooking spray or butter).
Place both loaf pans containing the dough in the warm oven (turned off) for at least an hour, to rise until double in size.
While the dough is rising, make the crust seasoning.
Crust Seasoning
Separate the egg white from the yolk (discard yolk or save for another use).
Combine egg white and water; whisk until combined.
Once the dough is double in size, preheat the oven to 375 degrees.
Using a pastry brush, gently apply the egg white mixture to the top of the bread (be careful not to make it fall).
Continuing to be careful, apply the herb paste to the dough.
Bake the loaves in the preheated oven for 25 minutes or until the top is crusty brown.
Notes
Alternatively, you may remove the bread a few minutes before it’s done baking and apply the egg white mixture and herb paste, then continue baking until done.