First, you need to make the tangzhong. In a small saucepan over medium-low heat, add the flour and water from the Tangzhong section. Slowly cook, stirring frequently with a spoon until you get a paste that looks like smooth mashed potatoes. 

Remove pan and tangzhong from the heat and allow to cool for around 10 minutes. 

In your mixing bowl, add all the ingredients for your Milk bread dough and by the time everything has been weighed and added to the mixing bowl, your tangzhong should have cooled enough to use it. Add the tangzhong as the last ingredient into the bowl.

Mix with your electric mixer's dough hook for 8 minutes. If you are mixing/kneading by hand, you will need to knead for at least 15 minutes. Whichever method you choose, your goal is to knead until you are left with a nice soft and smooth dough that might be a tiny bit sticky. 

Add dough to a lightly oiled bowl, cover, and allow to rest in a warm spot for an hour. 

After an hour, the dough should have doubled and become full of gas and bubbles. Deflate the dough and separate it into two equal pieces. You should use a scale at this point for more consistently shaped pieces of dough. Form each dough portion into a tight ball. 

Place both shaped dough balls, spaced evenly, into your 4x8 or 4x9-inch bread loaf pan. There will be space between the balls and in the corners of the pan, but the dough should rise to fill those gaps.

Near the end of the hour of rising time, preheat your oven to 350 degrees F (175 C). 

Make your egg wash with one whole egg plus a tablespoon of water. Whisk to combine and then carefully paint the egg wash on top of the risen dough. Try not to deflate the dough.

Bake the dough for 30 to 35 minutes, rotating the pan halfway through the bake time. Depending on your oven, you may want to peek and check for browning and doneness around the 28-minute mark. Continue baking if it's not glossy brown.