In a deep bowl, mix all dry ingredients: brown cane sugar, vanilla, baking powder, salt and flour.
Add soft butter to the dry mixture. Using your hands, mix all the ingredients until you have crumbs.
Break the chocolate bar into small pieces and add to the dough so that the chocolate pieces are evenly distributed throughout the mass.
Break the egg and stir until the crumbs form a soft ball of dough.
Form the resulting dough into balls, approximately the size of a walnut, and place on a baking sheet lined with parchment. Do not place the pieces close to each other, because the cookies will increase in size during baking. Using a fork, press down to flatten the cookies.
Place in an oven preheated to 180 °C with the “top-bottom” function turned on for 25 minutes.
Once the cookies are baked, place them on a flat surface until they cool, as they are soft and may warp. It is better to serve these cookies cooled, with any drink that suits your taste.