Cream the softened butter lightly, then mix in the sugar.

Add the egg and mix well.

Sift the all-purpose flour and salt into the mixture.

For the chocolate dough, sift cocoa powder along with the flour.

Add milk to each dough and mix thoroughly.

Place each dough in a plastic bag, shape as shown in the reference image, and refrigerate.

Stack the two doughs together.

Cut the dough as shown in the reference image.

Arrange the pieces in an alternating pattern to create a checkered design.

Cut into appropriate sizes.

Bake at 170°C for 15 minutes.