Add all ingredients (flour, milk powder, sugar, salt, yeast, softened butter, and water) to the bowl of a KitchenAid mixer fitted with the dough hook.
340 grams all purpose flour, 45 grams milk powder, 30 grams granulated sugar, 4 grams kosher salt, 4 grams instant yeast, 52 grams butter, 230 grams water
Mix on low speed until the dry and wet ingredients are combined. Increase speed to medium-high and continue mixing for 12-15 minutes, until the dough is smooth and elastic.
Transfer the dough to a lightly greased bowl, cover with plastic wrap, and let rest for 25-30 minutes.
Transfer dough to lightly floured work surface. Divide the dough into 6 equal portions. Shape each portion into a round ball.
Sprinkle the inside of the baker with semolina or corn flour. Place the dough balls in a stoneware baker with a tight-fitting lid. Cover and let rest for 25-30 minutes.
Brush the tops of the rolls with the beaten egg. Cover the baker with the tight lid.
1 egg beaten
Preheat oven to 475°F (245°C). Bake the covered rolls for 25 minutes. Reduce oven temperature to 375°F (190°C), remove the lid, and continue baking until the tops are golden brown (about 3-5 minutes).
Transfer the bread to a wire rack to cool completely before serving.