Make the Tangzhong: combine flour and milk in a pan and heat it on medium heat, constantly mixing until a paste with the consistency of pudding or mashed potato forms. Transfer to a bowl and let cool for 5-10 minutes.
Heat up milk for the bread dough into a microwave for 30s. It should be warm but not too hot to the touch. Pour the warmed milk into a mixing bowl and sprinkle a tsp of cane sugar (from the 40h cane sugar) on top. Then sprinkle on the active dry yeast. Allow the yeast to bloom, about 5-10 minutes.
While you wait for the yeast to bloom, measure out the goji berries and rinse it under cool water to clean it. Set aside. Measure out the walnuts and set aside.
Combine the remainder of the dry ingredients together: sugar, flour and salt in a separate bowl.
After the yeast has bloomed, stir in the Tangzhong and egg. Mix until well combined.
Attach your mixing bowl to your stand mixer and put it on speed 2 (or knead setting). Slowly add in your dry ingredients and allow it to knead for about 3-5 minutes or until the dough comes together in a rough ball.
While the dough is kneading, add the butter a little at a time. Once fully incorporated, keep kneading until the dough is smooth and passes the windowpane test. To check, gently stretch a small piece of dough — it should stretch thin enough for light to pass through without tearing easily.
Add in the goji berries and walnuts and allow the mixer to knead the dough until they are well incorporated. The goji berries should have broken down and give the dough a yellow color.
Shape the dough into a ball, cover and allow it to proof at room temperature for 1 hour.
Once the dough has proofed, transfer it to a lightly floured work surface and divide it into 9 even pieces about 70g each.
Roll out each piece into a ball and place it in a prepared baking dish. Cover and allow the dough to proof for 45min-1hr at room temperature. Alternatively, you allow the bread rolls to rise overnight in the fridge, covered, overnight and bake it the next day. Preheat the oven to 350F.
Make the egg wash by mixing together egg and water. Brush the top of the proofed rolls evenly with the egg wash. Bake the rolls for 25 minutes or until the tops have turned golden brown.
Allow the rolls to rest in the baking dish for 15 minutes. Then, transfer it to a cooling rack to cool completely. Enjoy!