Chop the chocolate into small pieces. In a bowl, mix the flour with sugar, salt, and baking powder. Add the butter and egg, and combine using a spoon. Add the chocolate. Knead the mixture by hand into a smooth dough. Put to the refrigerator for one hour. Form walnut-sized balls from the dough, then flatten each one and place on a baking sheet. Bake for 20 minutes at 180°C. Let it cool. Put chocolate flavored filling Lauretta between two cookies. Decorate as desired.