bread flour • cocoa powder, sugar-free • unsalted butter, cut into small cubes • baking powder • granulated sugar • salt • egg, about 60g • milk • chocolate chips • Milk for brushing, optional • Bake at 220℃ / 428 F for 3 minutes, then 190℃ / 374 F for 13 minutes, for a total of 16 minutes (preheat the oven to 220℃ / 428 F) • You can use soy milk instead of milk