• I use this Pullman loaf pan that measures 8.3x 4.8 x 4.5 inch on the exterior and the interior measures 7.5 x 4x 4.4 inch. It's a tall loaf pan. You can also a standard regular 8.5 x 4.5 x 2.75 inch loaf pan
• To adjust the recipe to different pan size, please see my post below

Prepare tang zhong:

• Place milk and the bread flour in a small saucepan. Whisk until there is no more lumps. Cook this mixture over low-medium heat until it reaches 65 C (149 F). Remove from the heat and cover with a plastic wrap, touching the tangzhong so the skin won't form. You can use it on the same day once it has cool down, but I highly suggest using this the next day. It improves the taste of the bread. Store this in the fridge

Make the dough:

• If you use active dry yeast, mix the yeast with 2 tablespoons of warm milk you are going to use in the recipe to bloom the yeast. Let it sit for 10 minutes until it is foamy and bubbly.
• Mix all the dry ingredients together in a mixing bowl. Make a well in the center and pour in the wet ingredients and the tang zhong you made earlier. Use a dough hook attachment to knead the dough on speed 2 until all the crumbly dough starts to come together into one mass, it may take about 2-3 minutes for this to happen. Don't be tempted to add any liquid. You may need to stop halfway and scrape the dough off the hook and the sides of the bowl and knead again several times 
• Once it comes into a rough dough, stop the machine. The dough will not be smooth, don't worry. Cover the dough and let it rest for 20 minutes. This is an important rest that bakers refer to as an autolyse (though in our case it's a short one. Read my post above for detail)
• After the rest, turn on and knead the dough again on speed 2 and knead for 1-2 minutes until it is a bit smoother. Then add the salt and sugar into the dough. Continue to knead until the dough is relatively smooth. You need to stop and scrape the dough off the hook and the bowl several times during this process. I promise it's worth the effort!
• Once you have a smooth dough, turn the machine back on again to knead and increase speed to 4. Gradually add in the softened butter a bit by a bit.  The dough will turn into a REAL sticky mess again because of the butter, just keep kneading and stop halfway and scrape the dough off the hook and bowl again and continue to knead until the butter is absorbed by the dough. IT WILL HAPPEN, don't worry! DO NOT be tempted to add any extra flour. You will get a shiny smooth dough that is very elastic. This may take about 10-15 minutes. The dough must pass a windowpane test, meaning, when you stretch a small amount of dough thinly, it won't break and a light can pass through

1st proofing:

• Place this dough in a lightly oiled large bowl, cover it with a clean and damp tea cloth or plastic wrap and let it rise at a warm place for about 1 hour until the dough doubles in volume

To bake the next day:

• If you don't plan to bake on the same day, deflate the dough and then round it up into a dough ball and keep in an air-tight container and put it in the coldest part of your fridge (not freezer) for up to 12 hours. I don't recommend any longer than that. Proceed to shaping

Shaping:

• Lightly oil your loaf pan all over. You can also use a non-stick spray. If the dough is cold from the fridge, let it sit at room temperature for about 15-20 minutes and the proceed to shaping
• Deflate the dough and separate it into 3 equal-weight dough. Cover the dough with plastic wrap and let them rest for 10 minutes to relax the gluten
• Roll each ball out into a rectangle shape (don't have to be exact). Fold the two long sides up and then roll it from the bottom to top. Place the seam side down in the loaf pan and repeat with the other 2 doughs. Place them next to each other. Cover with a plastic wrap

2nd proofing:

• Let the dough proof again for another 45 minutes to one hour (or longer depending on the temperature and the yeast you use) or until they fill up the loaf pan, about 90%. Brush the top of the dough with egg wash
• Sprinkle with some white sesame seeds or other seeds of your choice if you like
• 15 minutes before the end of proofing, preheat oven to 375 F (190 C) for conventional oven. If you use a convection oven, lower the temperature by 20 F or 15 C.

Baking:

• Put the pan on the middle rack and let it bake for the next 25-30 minutes depending on the oven, mine took about 25 minutes. The internal temperature on the center of the bread is at least 190 F (88 C). I highly recommend a digital thermometer to take out the guess work!
• Remove from the oven and remove the bread from the pan and cool down completely on the cooling rack. Enjoy and once it's cooled down completely, wrap it up with plastic wrap and it's good for about 3 days or so at room temperature (it didn't last that long in our house)