Soft Sourdough Milk Bread

Method

1. Make the tangzhong. Whisk the 25g flour and 125g milk in a small saucepan over medium-low heat. Stir constantly for 2–3 minutes until it thickens into a smooth paste with whisk lines visible. Scrape into a bowl, cover, and cool to room temperature (30–40 minutes, or fridge for 15).
2. Combine the dough. In a stand mixer bowl (or large mixing bowl), add the cooled tangzhong, warm milk, active starter, egg, sugar and bread flour. Mix on low with a dough hook until a shaggy mass forms — about 2 minutes. Cover and rest 30 minutes (fraisage).
3. Add salt and knead. Sprinkle over the salt and knead on medium for 5–7 minutes. The dough should pull cleanly from the sides of the bowl and start to slap-and-fold rhythmically. It will feel tacky but strong.
4. Butter in. Add the softened butter one cube at a time with the mixer running. It looks broken at first — keep going. After 6–8 more minutes of kneading the dough should be silky, glossy, and stretchy enough to pull a thin windowpane without tearing.
5. Bulk ferment. Transfer to a lightly oiled bowl. Cover and bulk ferment at 22–24°C for 5–7 hours, or until the dough has risen by 60–75% and jiggles when the bowl is shaken. (For a cold-retard option: bulk 3 hours at room temp, then refrigerate overnight; shape cold the next morning.)
6. Divide and shape. Turn onto an unfloured counter. Divide into 4 equal pieces (about 220g each). Roll each into a smooth ball, cover, and rest 15 minutes. Flatten each ball into an oval, letter-fold it, then roll it up tightly into a cigar shape. Place all four cigars seam-side down into a greased 900g (9x5") loaf tin.
7. Final proof. Cover loosely with a shower cap or oiled cling film. Proof 2–3 hours at 24°C until the top of the dough sits about 2cm above the rim of the tin and springs back slowly when pressed.
8. Bake. Preheat oven to 180°C (fan). Brush the top with egg wash. Bake for 32–38 minutes until deeply golden and the internal temperature reads 88°C. If it browns too fast, tent loosely with foil at 25 minutes.
9. Cool and serve. Turn out of the tin onto a wire rack. Rub the top with a knob of butter for shine and softness. Cool for at least 1 hour before slicing (patience preserves the crumb!). Best eaten day of, but keeps 3–4 days wrapped, and freezes well sliced.