Hokkaido Milk Bread: The Tangzhong Method

For the tangzhong: Whisk flour and water together in a small saucepan. Place over medium-low heat on the stove.Cook, whisking constantly, until the mixture thickens into a pudding-like consistency and you can leave lines in the mixture, about 5 minutes. You might be tempted to walk away from the mixture at the beginning when it's taking a while to thicken, but don't - it will come together surprisingly quickly and you don't want it to overcook. If you want, you can check the temperature - it's finished when it reaches 65 degrees C (149 degrees F), but I don't find it necessary.Let the tangzhong cool to room temperature before using. You can also store in the refrigerator for a couple days and bring to room temperature before using. If you see grayish spots in the tangzhong, discard it and make a fresh batch. For the bread: The milk should be at 108-110 degrees F to develop the yeast (any hotter and it will kill the yeast). Combine yeast and milk and 2 teaspoons of the sugar in a small bowl and let stand for about 5-8 minutes until yeast is bubbly. Combine the flour, sugar, and salt in the bowl of a stand mixer. Add in the yeast mixture, the tangzhong, and the egg.With a dough hook attachment, mix all the ingredients until it comes together into a soft, sticky dough, about 10 minutes.Add in the butter and mix to incorporate. Continue beating the dough for about 10-15 minutes until the dough is smooth and elastic. You should be able to stretch the dough out fairly thin without it breaking (the windowpane test). If it breaks right away when you try to stretch, mix it for a couple more minutes.Turn out the dough into an oiled bowl and cover with plastic wrap. Let proof for about 40 minutes until dough has doubled in size. The amount of time this takes will depend on the ambient temperature. I like to leave the bowl on top of the stove (no burners turned on) but with the oven turned to 250 degrees.When the dough looks like it has doubled in size and is puffy to the touch (if you poke the dough it should hold the indent and slowly fill back in), take the dough and split into 4 equal pieces. Roll each piece into a ball. Cover with plastic wrap and let rest for 15 minutes.Grease a 5"x9" loaf pan. Set aside.Roll one piece out on a lightly floured surface into a long oval. Fold the right third of the oval over the middle, then fold the left third of the oval over the middle to make a long, narrow packet. Lightly roll over the seam to flatten and seal.Roll the packet up from the bottom to make a fat roll. Repeat with other three balls of dough.Arrange the four rolls of dough, seam side down, in the prepared loaf pan. Cover with plastic wrap. Let proof for another 40 minutes until the dough reaches just below the rim of the loaf pan.Preheat oven to 350 degrees F while the bread is proofing for the second time.Brush the top of the bread with a little egg wash. Place in the oven and bake for about 30-35 minutes, until the top is dark golden brown and the bread is firm to the touch and sounds hollow when you tap it.Turn out bread onto wire rack and let cool before eating.