In a small saucepan, add the milk and flour. Cook for about 1-2 minutes over medium heat, whisking continuously until the mixture has thickened and resembles thick pudding.

Place the mixture into a small bowl, cover it with plastic wrap so it touches the surface, and leave to cool down to room temperature, or until just lukewarm.

In the bowl of a stand mixer fitted with a dough hook attachment (or use a hand mixer with hook attachments and a large bowl), add the flour, yeast, sugar, salt, eggs, and the tangzhong mixture. Knead on medium for 5 minutes or until the dough has formed and doesn’t stick to the walls of the bowl. It should be sticky to the touch.

Lower the speed to medium-low and start adding the butter, one tablespoon at a time. Don’t add another portion until the previous one has been incorporated into the dough. The whole process will take approximately 10 minutes. Scrape the bottom and the sides of the bowl and remove the dough from the hook a couple of times during the process.

Once all the butter is in, knead the dough on medium for 10 - 15 minutes or until you can stretch a small piece of it into a square, creating a film thin enough for light to pass through. The dough should not tear at all or tear just a little bit only on the edges while performing the so-called windowpane test.

Cover the bowl with plastic wrap and leave it in a warm place to proof for 1 - 1.5 hours or until it doubles in volume. You can also, place the covered bowl in the fridge overnight.

Punch the dough down and remove it onto the working surface. If it sticks too much, dust it lightly with flour. Divide it into 8 pieces (90g each) and shape them into balls. Place onto 2 baking sheets lined with parchment paper leaving 2” (5cm) in between. Cover with plastic wrap and leave to proof at room temperature for 40 min - 1 hour.

Meanwhile, preheat the oven to 375F (190C).

When the buns have risen and the oven is hot, brush the top of each one with an egg wash and sprinkle flaky sea salt on top (optional).

Bake on the lowest ⅓ of the oven for 15 - 18 minutes. Cover with a piece of foil after the 12-minute mark if browns too quickly. The top should be a deep brown color and the buns should sound like they’re hollow inside when you tap on them.

Remove from the oven and place on a cooling rack to cool down. Bake the second batch.