Anpan

Directions

1. Combine the dry yeast, cake flour, bread flour, sugar, and kosher salt in a large mixing bowl.
2. Beat the egg lightly in a small bowl and then add it to the bowl with the dry ingredients.
3. Add the warm milk and warm water to the dry ingredients.
4. Mix the ingredients together until well combined and a sticky dough forms, around 2 minutes of mixing with hands or a wooden spoon. Shape the dough into a loose ball.
5. Transfer the dough to a lightly-floured surface and punch the dough with your hands by folding the top half of the dough in half back toward you and then pressing forward with your palms. Rotate the dough slightly, fold it in half, and press into it again with your palms. Repeat the process for 5–8 minutes. If the dough does not lose its stickiness, slowly add more flour, but do not over-add.
6. After punching the dough, it should be soft and smooth. Stretch the dough out flat so it is around 10 inches in length.
7. Place small cubes of butter on top of the dough, roll the dough up, and continue kneading. As you knead, the dough will absorb the butter and it will eventually become very smooth and easier to work with.
8. Begin slapping the dough down onto the work surface, then fold it in half away from you. Repeat several times to create an elastic dough. Slap the dough, turn it 90 degrees, and punch it down. Continue this process until the dough is supple and elastic, approximately 10 minutes. Don’t let the dough rest on the surface for too long in between turns.
9. Near the end, pull the end of your dough with your thumb and fingers. Keep spreading the dough with your fingers, stretching the dough into a thin translucent membrane. When it does this without tearing, the dough is ready to rise.
10. Shape the dough into a ball by pulling all sides of the dough to the bottom and pinching them together.
11. With the seam on the bottom, place dough in a bowl and cover with plastic wrap. Allow dough to rise in a warm place until it is doubled in bulk, around 2 hours.
12. Remove the dough from the bowl onto a clean surface. Press the dough with your hands to release gas in the dough and deflate.
13. Fold both sides of the dough toward the center, then fold in thirds toward the middle. Flip, keeping the seam side on the bottom.
14. Shape the dough into a ball, rotating with both hands while keeping the seam touching the surface.
15. Cut the dough into eight equal pieces.
16. Shape each dough piece into a round ball, pulling from all the sides and tucking into the bottom. Place the dough on your palm and rotate it with the opposite hand, keeping the seam side on the bottom.
17. Put the dough on a baking sheet lined with parchment. Cover the dough with plastic wrap and let rest for 15 minutes at room temperature.
18. Flatten the dough with your hand, fold in thirds twice, and shape it into balls.
19. Press the dough so stretches to 3 inches in diameter. Put a spoonful of red bean paste in the middle of the dough, then pull all sides of the dough around and wrap the red bean paste tightly to seal.
20. Pinch the seam very well and put the seam on the bottom. Place the dough on your palm and rotate it with your opposite hand a few times, keeping the seam on the bottom.
21. Place the dough back onto the baking sheet, seam side on the bottom.
22. Cover the dough with plastic wrap to prevent from drying. Let the dough rise in a warm place until the dough has doubled in bulk, about 30 minutes.
23. While the dough rises, preheat the oven to 400°F. 

For Topping:

24. Whisk together the egg and water in a small bowl.
25. Brush the rolls with the egg wash.
26. Sprinkle the rolls with sesame seeds.
27. Bake for 13–15 minutes. If the rolls are not browning equally, rotate the pan.
28. Remove from oven and transfer to a wire rack to cool. Serve immediately or store in an airtight container after completely cooled.