In a small saucepan, heat the milk with butter over low heat just until the butter melts. Remove from heat and add to the bowl of a standing mixer fitted with a dough hook. Proof the yeast by adding it to the warm milk and butter. Add the sugar and stir gently to dissolve. Let stand 3 minutes until foam appears. This indicates the yeast is active. Turn mixer on low and gradually add the flour. When the dough starts to come together, increase the speed to medium and add the salt and 1 egg white. Stop the machine periodically to scrape the dough off the hook. Mix until the dough is no longer sticky, about 10 minutes.
Turn the dough onto the work surface and knead for a minute or so by hand. Knead by folding the dough over itself and pushing out with the heel of your hands, not down. Rotate the dough and repeat. The dough is properly kneaded when you can pull it and it stretches without breaking. Form the dough into a round and place in an oiled bowl, turn to coat the entire ball with oil. Cover with plastic wrap or a damp towel and let rise over a gas pilot light on the stovetop or in another warm place until doubled in size, about 45 minutes. Test the dough by pressing 2 fingers into it. If indents remain, the dough is adequately risen.
Once the dough is doubled and domed, turn it out onto the counter. The act of turning out the dough naturally deflates the gas, so there is no need to aggressively punch it down. Handle the dough gently, overworking the gluten at this point will produce a dense loaf that is difficult to shape. *To form a loaf, pat the dough into a rectangle, fold the long sides to the middle then fold under the ends. Pinch the seams closed and place in a greased 9 by 5-inch loaf pan, seam side down. Make sure the dough touches all sides of the pan. Cover with plastic wrap and let rise a second time for 20 minutes or until the top of the dough is nearly level with the top of the loaf pan. Preheat oven to 350 degrees F, place a large pan on the bottom rack of the oven. Bring 3 cups water to a boil on the stove. Pour the hot water into the preheated pan to create a steam bath for the bread. This will make a crisp crust.
Slash dough down the middle of the loaf with a sharp knife to allow the steam to escape during baking. Brush the top with remaining beaten egg white and sprinkle with sesame seeds. Bake the bread for 30 to 40 minutes until crust is golden and internal temperature reads 195 degrees F when checked with an instant read thermometer. The bottom of the loaf should sound hollow when tapped. Immediately remove the bread from the pan and cool completely on a rack.
* Variation: To make Cinnamon-Raisin Swirl Bread: after the first rise, press the dough out to a rectangle, sprinkle surface with cinnamon and raisins to cover. Roll up like a jellyroll, pinch the seams closed and continue as directed in the recipe.