Mix flour and powdered sugar together in a large bowl or dough bowl.

Cut the butter into smaller pieces and add them to the flour mixture.

Rub the butter into the flour mixture until it is finely crumbled and resembles grated parmesan.

Gather the dough together with the egg.

Knead all the ingredients together until the dough is uniform. Knead as briefly as possible, stop when the dough comes together.

Divide the dough into two portions.

Incorporate cocoa into one portion.

Divide each portion of dough into 6 equal parts.

Shape each portion of dough into uniform sticks.

Beat the egg with a fork in a deep plate.

Brush each dough stick with egg and lay them together, so that one brown and one white is on the bottom. Lay the others on top in the opposite arrangement.

Wrap the finished dough rolls in baking paper and press them into square sticks.

Place the sticks in the refrigerator until they are completely cold.

Cut into slices approximately 5 millimeters thick.

Place the cookies on baking sheets lined with baking paper.

Bake the cookies for 6-8 minutes at 200 degrees Celsius (392 degrees Fahrenheit) (180 degrees Celsius (356 degrees Fahrenheit) with fan).

Let the finished cookies cool on a wire rack.