For the Tangzhong

1. Cook the milk and the flour in a saucepan over medium-low heat for around 2 to 3 minutes; keep whisking until it turns into a paste.
2. Transfer the paste into a small bowl and let it cool down to warm before using.

For the loaf

1. Place around 1 tablespoon caster sugar and the yeast into the warm milk. Stir and mix them well. Cover with a small towel for around 5 – 10 minutes or until the surface of the mixture becomes foamy.
2. Add flour, salt and the remaining caster sugar into the mixing bowl of a stand mixer. Begin to mix by hand, using a spatula. Mix thoroughly and gradually create a well in the centre of the mix. Pour in the egg, a bloomed yeast mixture and cooled tangzhong.
3. Attach a dough hook and start kneading the mixture at low speed until everything comes together. Gradually add the softened butter, a little at a time.
4. When all the butter is incorporated, turn the mixer to medium speed. Continue to knead for 5 to 10 minutes or until it passes the windowpane test. This involves taking a small piece of dough and gently stretching it until it is thin enough to see light through it, without it tearing.
5. Divide the dough into two equal portions using a scale, total weight 705 g, approximately 353 per portion. 
6. Place one portion back into the mixer and knead in black sesame tahini until fully incorporated.

First Proof

1. Place both doughs in separate greased bowls, cover, and let them rise until doubled in size (about 2 hours).

Shaping the Dough

1. Lightly flour a work surface, release the air, and shape both dough portions into separate balls.
2. Cover and rest for 15 minutes.
3. Roll each dough into a 21 x 34 cm (8 x 13 inches) rectangle.
4. Place the milk bread dough on top of the black sesame dough and align them neatly.
5. Turn the dough 90 degrees and roll again into a 21 x 34 cm (8 x 13 inches) rectangle (be careful with your pressure to keep the two separate layers intact).

Create the Accordion Shape

1. Fold the black sesame dough over the milk dough like a book, then fold the milk dough over (two folds).
2. Roll the folded dough into a log shape.
3. Score the dough with a bread lame to create the accordion pattern.

Second Proof & Baking

1. Place the shaped dough into a pullman loaf tin, (no need to line / grease). Cover and let it rise for another 45 minutes to an hour.
2. Preheat the oven to 180°C (350°F).
3. Brush the top with egg wash for a golden finish.
4. Bake for 30 minutes, covering with foil at 20 minutes to prevent over-browning.

Cooling & Serving

1. Transfer the bread to a wire rack and let it cool for 30-60 minutes.
2. Slice and enjoy the fluffy, nutty, and mesmerising swirl bread with some butter!