Measure 30 g of mizuame (sugar syrup) into a measuring cup, add warmed milk up to the 235 ml level, and mix well.
Put all the ingredients into a bread machine, use the dry yeast program + the dough-only program up to the end of the 1st rising, and leave the dough as-is until it has doubled in volume.
When the dough has doubled in volume, take it out and deflate lightly. Divide into 3 pieces, round off each piece, cover with plastic wrap to prevent it from drying out, and leave to rest for 15 minutes.
Deflate the dough completely, and roll out each piece flat. Fold in the sides towards the center, and roll up the dough. (Make sure not to let any air in.)
Roll up all 3 pieces of dough, put in the baking pan, and mist well. Cover the pan with plastic wrap and leave to rise for 45 to 60 minutes (2nd rising) until the dough fills the pan about 80% of the way.
When the dough has filled the pan about 70%, start preheating the oven with the baking sheet inside to 180°C. When the oven has heated up, dust the top of the dough with bread flour, and put the lid on.
Put 4 layers of newspaper on top of the heated baking sheet, place the bread pan on top of that, and close the oven door.
Lower the oven temperature to 160°C, and bake for 18 minutes. Open the oven, quickly cover the pan with aluminum foil, and lower the temperature to 140°C. Bake for another 12 minutes, for a total of 30 minutes.
Since this just barely cooks the square loaf through to the middle, it's best not to change the baking at the higher temperature for 18 minutes + baking for a total of 30 minutes procedure.
When the bread is baked, open the lid of the baking pan and drop the pan from about a 15 cm height to prevent the bread from collapsing. This bread is very soft so it's important to do this.
This is how the loaf looks from the side. The top tends to brown so it's protected with a layer of bread flour just in case, but the sides are OK as-is.
After the loaf has cooled down a bit, I tried opening up one of the seams (in between the 3 pieces of dough) with my fingers. Can you see how fluffy and soft it is?
By deflating the dough very well after resting the dough, the finished bread should have a fine, even crumb.
Story Behind this Recipe
Ever since I learned how to make white rolls, I wanted to try making that snow white square bread that's sold in stores! So, after many attempts I succeeded at last.
I used to have 2 ways of baking this, but I consolidated it into the method that worked best for most people. When this is freshly bakes it's really tender, so please handle it very, very gently.