Making the Buns

• In a stand mixer with a dough hook, mix bread flour, sugar, salt, instant yeast, and milk powder. Add in milk, heavy cream, and egg, and knead on low speed for 10 minutes. The dough will be tacky; don't add more flour. Cover and rest for 2 hours or until it doubles in size.
• Flour a work surface and portion the dough into 9 equal pieces. Form each into a ball by tucking and pinching in the sides towards the middle. Cover loosely with plastic wrap.
• Use your hands to stretch the dough into a 4 inch circle, keeping the center thicker. Place ¼ cup of red bean paste in the middle. Bring the sides of the dough towards the center and pinch to seal. Roll in between your hands to smooth out the seam and form a ball. Place the bun seam side down on a baking sheet lined with parchment paper. Repeat with remaining dough.
• Dust your hands with a little flour and press down on the buns to flatten them slightly. Use scissors to cut 5 slits into the dough.
• Let the buns rest for 30 minutes to 1 hour in a warm area or until they almost double in size. While the buns are resting, preheat the oven to 350°F.
• Mix egg yolk and milk and brush over the buns. Sprinkle sesame seeds on top. Bake for 20 minutes. Serve warm.