Pour the water, milk, and bread flour into a saucepan, and place it over medium heat for 2-3 minutes, whisking constantly until it thickens into a custard-like paste. When thick and pasty, remove it from the heat and let it cool to room temperature.

Mix the yeast and 50ml of warm water in a bowl, and leave it to activate for 5 minutes, until it turns bubbly. Meanwhile, sift the dry ingredients (bread flour, sugar, and salt) into the bowl of a stand mixer. Add in the milk, yeast, and tangzhong starter to the dry ingredients. Then, start the mixer on low speed, with a dough hook attachment. Finally, add in the egg and softened butter, and mix it on medium speed for 15-20 minutes, until the dough becomes smooth and elastic. You’ll know the dough is ready when it almost shines a little, and it should pass the windowpane test.

When the milk bread dough is mixed and kneaded, shape it into a smooth ball, tucking the edges under the bottom. Place it in a bowl and cover with a kitchen cloth, and let it proof at room temperature for an hour, or until it has approximately doubled in size.

While the milk bread dough is proofing, ready a second bowl for the crispy crust dough. Sift the all-purpose flour, milk powder, baking powder, baking soda, and salt. With a whisk, cream together the butter and sugar. Then, add in the egg yolk, milk and vanilla extract, and mix until properly incorporated. Then, add in the dry ingredients, and knead it all together (you can do this by hand; it’s much faster, and you get the joy of squelching dough) until it forms into a dough. Divide this dough into 12 pieces, roughly roll each piece into a ball, and set aside.

While you’re still waiting for your milk bread dough to finish proofing, go ahead and line two baking trays with baking paper. (If you only have one, don’t worry, we’ll bake them in two batches.) Then, heat up your oven to 180°C.

When the milk bread dough has doubled in volume, punch it down knead for 2-3 minutes to force most of the air out of the dough. Then, divide the dough into 12 equal pieces (~85g each), and roll each piece into a ball. Then, using a small rolling pin, roll out the crispy crust dough balls into flat discs around 8 cm (3 inches) wide, and place it on top of each rolled-out milk bread dough balls so it covers most of the top.

Transfer the doughs onto the lined baking tray(s), leaving at least 8 cm (3 inches) of space between each ball for it to expand. Brush the eggwash on the dough, then gently score on a cross-hatch pattern on the crust, and pop it into the oven to bake for 15-18 minutes.

When the buns are burnished and baked through, remove them from the oven, and let the buns cool on a wire rack. You can eat it warm or at room temperature, just plain or with butter, spam, ham, or scrambled eggs, for breakfast, lunch, tea, or dinner. Or, if you’re saving it for the next day, just reheat it in a toaster oven before chowing down.