Make a quick tangzhong-style paste: In a small saucepan, whisk 3 tablespoons bread flour with 1/2 cup milk and 1/2 cup water. Cook over medium-low heat, whisking, until it thickens to a smooth, pudding-like paste, about 2–3 minutes. Remove from heat and let cool until just warm, not hot.

Mix the dough: In a mixing bowl, combine 3 1/4 cups bread flour, 3 tablespoons sugar, 2 teaspoons instant yeast, and 1 teaspoon fine salt. Add the cooled paste, 1 beaten egg, and 1/2 cup warm milk (about 100–105°F). Stir until a shaggy dough forms.

Knead and add butter: Knead by hand or with a stand mixer (dough hook) until the dough is starting to smooth, 5–7 minutes. Add 4 tablespoons softened unsalted butter, one piece at a time, mixing until fully incorporated. Continue kneading until the dough is elastic, smooth, and slightly tacky, 8–10 more minutes. It should stretch thin without tearing (windowpane test).

First rise: Shape into a ball and place in a lightly oiled bowl. Cover and let rise in a warm spot until doubled, about 60–90 minutes. If your kitchen is cool, it may take longer—be patient.

Prepare the pan: Grease a 9x5-inch loaf pan (or a Pullman pan without the lid). Line the bottom with parchment for easy release.

Shape the loaf: Turn the dough onto a lightly floured surface. Divide into 3 equal pieces. For each piece, flatten into a rectangle, then roll up tightly from the short side like a jelly roll. Pinch the seam and place seam-side down in the pan, side by side.

Second rise: Cover the pan and let the dough rise until it reaches about 1 inch above the rim (or just below the rim if using a Pullman lid), 45–75 minutes depending on temperature. The dough should look puffy and spring back slowly when gently pressed.

Preheat and glaze: Preheat the oven to 350°F (175°C). For a tender, burnished top, brush the loaf lightly with milk or a thin egg wash (1 egg beaten with 1 tablespoon milk). Don’t overdo it—light is best.

Bake: Bake for 28–35 minutes, until the top is deep golden and the interior reaches about 190–195°F. If the top browns too fast, tent with foil for the last 10 minutes.

Cool properly: Let the loaf rest in the pan for 10 minutes, then transfer to a wire rack. For the softest crust, lay a clean kitchen towel loosely over the loaf as it cools. Wait at least 1 hour before slicing.