Remove the baking tray from the oven and preheat the oven to 180 °C fan. Place the butter in a mixing bowl and mix it briefly with a mixer until soft. Then add the cookie mix and the egg and knead everything with the dough hooks into a cohesive dough. Fold the chocolate chips into the dough.

Roll the dough into a log of about 20 cm and cut it into 8 equal slices. Place the slices on the baking tray and slide it into the centre of the preheated oven. Bake the cookies for about 10 minutes until golden brown and cooked through.

Please note: the cookies are still soft when you take them out of the oven. Let them cool for 5 minutes on the baking tray first, then for about another 30 minutes on a wire rack, so they can firm up.