Prepare your Tangzhong: To a small pot, add your water then whisk in the flour. Place over medium heat and cook, whisking frequently, until the mixture has thickened up completely and resembles a thick paste. Transfer to a small bowl and cool to room temperature.

Activate the Yeast: In the bowl of your stand mixer fitted with a dough hook, combine the water, honey and yeast. Gently mix then allow it to sit in a warm place for about 10 minutes to activate. The mixture should be foamy and fragrant after 10-15 minutes.

Make the Dough: Once the yeast has been activated, add in the milk, duck fat, yolks and sugar and whisk to combine. Follow that with the salt and 5 ½ cups of flour, reserving the remaining flour off to the side. Mix everything on low speed on your mixer fitted with the dough hook for about 5 minutes.

Check the dough. It should be slightly sticky, but not stick all over your hands if you touch it. If it cannot handle the dough without it sticking all over the place, add the additional ½ cup of flour and mix it in. Knead it by hand for an additional 5 minutes before placing it into a bowl, covered with plastic and a kitchen towel to rise for about 2 hours, or until doubled in size.

Shape the Rolls: After the dough has doubled in size, dump it out onto your work surface and shape it roughly into a rectangle. Cut the rectangle into 12 even portions, then shape each ball into a round.

Place the balls into a baking dish brushed with duck fat to prevent sticking, then cover with a kitchen towel and allow to rise for another 1-2 hours, or until doubled in size again.

Bake the Rolls: Turn your oven to 350°F. Add the egg to a small bowl and whisk it together. Gently brush the tops of each roll with the egg wash, then top each roll with a generous pinch of flaky salt. Bake the rolls for 25-30 minutes, or until evenly brown all over and cooked through in the middle. Serve hot, brushed with additional duck fat or melted butter.