Mix bread flour, sugar, salt, and dry yeast together.
Add milk and egg, then knead the dough.
Add room temperature butter and knead again, then let ferment for the first rise.
Make cookie dough (cake flour, butter, sugar, and egg), then refrigerate.
Divide bread dough and shape into balls.
Roll out the cookie dough, cover the bread balls, and score with a grid pattern.
Let them proof for the second rise.
Bake in a preheated oven at 180℃ for 15 minutes.