Whisk together the 25 grams of flour and 100 ml of milk in a saucepan. Cook over medium-low heat while stirring continuously until it reaches a pudding-like consistency. Set it aside to cool to room temperature.

Using a stand mixer equipped with a dough hook, mix the 350 grams of flour, 60 grams of sugar, and 1 teaspoon of salt in a bowl.

Add the instant yeast, Tangzhong, 30 grams of soft butter, 1 large egg, and 130 ml of lukewarm milk. Mix for about 12 minutes at medium-low speed until the dough becomes smooth and no longer too tacky.

Form the dough into a ball and coat it lightly with oil. Place it in a bowl, cover it with a kitchen towel or plastic wrap, and let it rise until it doubles in size (about 30 minutes to 2 hours, depending on room temperature).

Gently punch down the dough and transfer it to a greased surface. Roll it into a rectangle, approximately three times the length of your loaf pan.

Fold it like a letter, bringing the right side over the center and then the left side over that. Roll the dough from the end closest to you towards the far end, like a jellyroll.

Place the dough seam-side down in a greased 5"x9" loaf pan. Cover it with a kitchen towel and allow it to rise again until it doubles in size.

Preheat your oven to 180°C (350°F). Bake the loaf for about 20 minutes, positioning the pan on a lower or middle rack.

While the bread is baking, beat the additional small egg with 1 tablespoon of water in a small bowl until frothy. After 20 minutes, remove the loaf from the oven, brush the top with the egg wash, and return it to the oven to bake for another 10-15 minutes or until the top is golden brown and shiny.

Once done, take the loaf out of the oven and let it cool for a few minutes. Remove it from the pan and let it cool completely before slicing with a bread knife.