Cream butter and brown sugar for the inner dough until smooth.

Add 1/2 beaten egg to the inner dough and mix well.

Sift and mix the dry ingredients into the inner dough: cake flour, cocoa powder, baking powder, and baking soda.

Wrap the inner dough in plastic wrap and refrigerate for 30–40 minutes.

Cream butter and white sugar for the outer dough until smooth.

Add 1/2 beaten egg to the outer dough and mix well.

Sift and mix cake flour into the outer dough.

Wrap the outer dough in plastic wrap and refrigerate for 30 minutes.

Roll the inner dough into 10g balls and the outer dough into 8g balls.

Flatten the outer dough into a thin disc and wrap it around the inner dough ball.

Press the wrapped dough balls slightly flat and place them on a baking tray.

Bake in a preheated oven at 180°C (356°F) for 7–10 minutes.