If the dough is ready, it will hold the shape after poking it.
Divide it into 8 equal pieces, 35g each.
Roll the divided dough into balls.
Cover the dough with plastic wrap, and let it rest for 15 minutes.
Divide the frozen butter and matcha butter into a total of 8 pieces, 5g each.
Take one dough out and roll it to flatten it. Place the (matcha) butter on top.
Seal the dough well with the butter inside. Repeat the steps for all dough.
Cover with plastic wrap, and let it rise for 1 hour or until 2x its size.
Preheat the oven to 170 °C or 338 °F.
Transfer the dough carefully onto the baking sheet.
Cut the ends of the piping bag. Starting from the middle top of the bun, start piping forming a coil/spiral until you have covered about 3/4 of each bun.
Bake for 8-10 minutes or until the top is crisp and golden brown.
Let the bread rest in the pan for 5 minutes, then transfer to a cooling rack to cool further. Ready to serve.