• Toast the walnuts on a dry pan over medium-low heat until lightly golden brown and smell nutty, about 5 minutes. Let them cool down as you prepare the dough, then finely chop into tiny pieces
  

Prepare the dough:

• Combine all the ingredients for the dough, except for the butter, which we will add last, to the mixing bowl of a stand mixer fitted with a dough hook attachment. Give it a quick stir so the dry ingredients won't "fly" all over when you start the machine. Start kneading on a low speed for 2-3 minutes and then increase the speed to medium and knead for another 2 minutes until you form a rough dough.
  
• Gradually add the butter, one pat at a time, and continue to knead over medium speed until the dough is smooth and elastic, you may need to stop the mixer halfway and scrape the sides of the bowl. The dough will be sticky, but don't be tempted to add more flour. It clears the side of the bowl but still sticks to the bottom of the bowl. This may take 8-10 minutes of kneading
  

First proofing:

• Lightly oil your hands, scrape the dough using a dough scraper, and pick it up with your hands to round it up into a smooth dough ball. Lightly oil the bowl and place the dough back into the bowl.
  
• Cover with a plastic wrap and let it proof at a warm place until the dough is doubled in volume. This may take somewhere from 1 – 2 hours depending on the temperature. When you poke your finger into the dough, the indentation stays and the dough doesn't deflate
  

Shaping:

• Lightly grease a 9x9 inch pan and line with two pieces of parchment paper perpendicular to each other, overhanging on the side
• Lightly flour your work surface. Turn the dough out and press into a rectangle. Roll into a 10×14 inch sheet with the long side near to you. Spread the red bean paste filling evenly on the surface, leaving a ½-inch border on all sides. Scatter the chopped walnuts as evenly as possible on top of the red bean paste
  
• Roll the dough away from you, tightly into a log.
  
• Pinch the seam to seal.
  
• Use a serrated knife and slice into 9 pieces.
  
• Arrange in the prepared pan
  

Final proofing:

• Cover and let rise until puffy and the dough fills up the pan nicely, about 45–60 minutes at a warm temperature.
  

Bake:

• Preheat oven to 350 F (180 C) for conventional oven, 330 F (165 C) for convection oven
• Bake for 30 minutes, or until pale golden brown and the internal temperature reaches 190 F (88 C).

Prepare the glaze:

• 5 minutes before the end of baking time, combine all ingredients for matcha glaze. Whisk until smooth
  

Glaze the bread:

• Remove the bread from the oven and set on top of a cooling rack.
  
• Pour or spread the icing on top of the warm rolls. Serve warm or at room temperature