Heat milk in the microwave until hot, but not boiling. Stir in 2 tablespoons of the sugar, salt and butter. Set aside to allow butter to melt. Cool to lukewarm.
Place warm water in your mixing bowl; sprinkle in yeast and remaining one tablespoon of sugar; stir until dissolved. Let sit for 5 minutes or so to allow yeast to proof.
Add lukewarm milk mixture and 3 cups flour; beat on medium-low until smooth. Add enough additional flour to make a soft dough. You may or may not use all the flour. Turn out onto lightly floured board. Knead until smooth and elastic, about 8-10 min.
Form into smooth ball and place in greased bowl, turning to grease top. Cover with a clean, soft towel; let rise in warm place, free from draft, until doubled in bulk, about 30 minutes.
Punch down dough and let rest 15 minutes.
Divide dough in half and shape each half into a loaf. Place each loaf in a greased 9x5x3 bread pan. Cover; let rise in warm place, free from draft, until doubled in bulk, about 45 minutes.
Whisk together the egg and water to make an egg wash. Gently brush the egg wash onto the tops of both loaves right before placing in the oven.
Bake at 400 degrees F, about 30 minutes, or until done.