Make the tangzhong by combining ½ cup whole milk, ½ cup water, and ¼ cup bread flour
Cook the mixture while stirring to form a paste
Let the tangzhong cool completely
In a bowl, combine 1 cup warm water, 10 grams active dry yeast, and 2 tablespoons sugar
Let the yeast mixture sit for 10 minutes until foamy
In a large mixing bowl, combine 4 ½ cups bread flour, 2 teaspoons kosher salt, and 2 tablespoons sugar
On low speed, add the egg, egg yolk, yeast mixture, and cooled tangzhong to the dry ingredients
Add ¼ cup unsalted butter and knead on low speed for 10 minutes until dough is sticky
Oil a large bowl and transfer the dough to it
Cover and proof until doubled in size, about 1 to 1 ½ hours
Punch down the dough and divide into 18 pieces
Shape each piece into a roll and place in a spritzed extra large baking dish
Cover and proof again until doubled, about 1 hour
Brush the rolls with egg wash
Bake at 375 degrees for about 20 minutes until lightly golden
While still hot, brush the rolls with melted unsalted butter and sprinkle with salt
