Start by making the tangzhong base. In a microwave-safe bowl, add ½ cup of water plus 3 tablespoons of all-purpose flour. Whisk ingredients until there are no lumps remaining. Microwave the mixture for 20 seconds, stop and whisk it. Repeat 2 times more, always remembering to pause and whisk. Mixture will be smooth and pudding-like when ready. Let it cool for 5 minutes.

In a large bowl, or the bowl of your stand mixer if using one, mix all dry ingredients: flour, milk powder, instant yeast, sugar and salt.

In a medium bowl, mix the tangzhong base with egg and whole milk.

Add wet mixture to the dry mixture and mix until dough is formed.

Add room temperature butter and knead the dough for 5 minutes if doing it with a stand mixer, 8 to 10 minutes if doing it by hand. Dough should feel slightly tacky, and if doing using a stand mixer, stick to the bottom of the bowl but not to the sides.

Let the dough rest in a warm spot, covered, for 1h to 1h and 30 minutes, or until it doubles.

Line and grease with butter a deep 9x4 inch loaf pan.

Divide dough into 4 equal pieces. In a floured counter, roll each piece open, then roll each strip of dough into a cylinder, and pinch ends to seal. When arranging rolled dough into the loaf pan, remember to place the pinched side facing down, with the spiral against the long side of the pan.

Let the dough rest again for 1 hour, or until it almost doubles. Dough should look puffy when ready.

Bake shokupan for 35 to 40 minutes at 350°F, until top has a deep golden brown color. Don’t bake at a higher temperature, and bake for at least 30 minutes or it will be undercooked in the middle.

Wait for at least 1 hour before slicing, so bread will be cooled and fully cooked.