Directions

• Heat ingredients in a small saucepan over medium-high heat, constantly stirring until it turns into a thick paste. Transfer to a small bowl and cover it with plastic wrap to prevent a dry skin.
• Let the Tangzhong chill in the fridge until it cools down to room temperature.
• Mix bread flour, sugar, salt and yeast. Add milk, egg, and cooled Tangzhong. Mix on low in a stand mixer until everything is combined (~ 2 mins).
• Add softened unsalted butter and mix on medium speed until a soft dough forms (~5 mins).
• If the dough is too sticky, add a bit of flour a few tbsp at a time. Finish off by hand kneading the dough, then shape it into a smooth ball.
• Place it in a lightly oiled bowl and cover it with plastic wrap. Let dough rise in a warm spot (80-85°F in oven) for an hour until doubled in size. *Make topping at this point*
• After an hour, weigh the dough and divide it into 9 equal pieces, then cover it with plastic wrap and let it rest for 15 mins. After 15 mins, knead each piece of dough one last time and shape it into a smooth round ball. Transfer to a baking sheet lined with parchment paper and cover it with plastic wrap for the final rise in the oven (~40 mins).
• Cream butter, then add sugar and continue to cream together. Then add egg yolk, milk powder, milk and mix all until combined. Add baking soda, baking powder, and cake flour. Mix together until is forms a thick paste. Transfer it onto plastic wrap and shape into a small log.
• When the buns are done their final rise, weigh the topping and divide into 9 equal pieces. Flatten each piece out onto plastic wrap (for easy transfer), and roll it into a circle around 4.5 inches. Transfer it onto each bun.
• Finish off by brushing each bun with egg yolk.
• Bake at 360°F for 14 mins.