Steam the mung bean for 30 minutes, or until softened.

Place cooked mung bean, sugar, coconut oil and tapioca starch into a food processor. Blend until very smooth.

Pour the mung bean paste in a small pot, turn on heat and cook the paste until very dry. Stir with a wooden spoon and reduce the heat to prevent burning.

Add in matcha powder and mix well. Remove from heat and let it cool completely.

Cut salted egg yolks into half, if using.

Place ½ teaspoon of Shaoxing wine or brandy on the yolks.

Microwave the yolks for 15-20 seconds or until the yolks has oil appear and become solid, not completely cooked, about 80% cooked. Cool completely.

Divide the cooked mung bean mixture into 6 portions, about 43-45g each and form into balls.

Make a well with your thumb and place one ½ egg yolk in the well.

Enclose the yolk with your thumb and index finger to seal the yolk inside. Roll it until it is smooth and round. Repeat with the remainder.

Rest, cover and chill in the fridge until ready to use.

Mix all-purpose flour, icing sugar, matcha powder (or red yeast rice powder) and clarified butter into  a bowl.

Add water and knead into very smooth and elastic dough.

Divide it into 3 portions, about 38g each.

Cover and let rest for 20-30 minutes.

Mix together cake flour and clarified butter until it can be squeezed together into a ball.

Divide into 3 portions, about 24g each. Form into balls.

Flatten a water dough ball with your palm and place an oil dough ball in the center, enclose it and form a ball. Repeat with the remainder.

Cover and let rest for 15 minutes.

Flatten a dough ball with your palm and roll it flat into an oval shape with a rolling pin.

Start rolling the dough at an angle and roll diagonally into a long Swiss roll. Let rest for 15 minutes.

Flatten the Swiss roll with your palm slightly and roll flat into an rectangular long piece with rolling pin.

Swiss roll the piece into a stubby short roll.

Cut the roll in half with a serrated knife.

Flatten one piece with the cut side down using a rolling pin (to the size of your palm).

Flip the dough over with the cut side up.

Repeat the with the remainder and let rest for 15 minutes in the fridge before baking.