For the orange cookies, crumble flour with cold butter, add egg, sugar, salt and orange sugar and quickly knead into a shortcrust dough. Let the dough rest for 30 minutes, then roll out to about 3 mm thick and cut out rectangular cookies.
Bake in the preheated oven at 180 ° for about 10 minutes, let cool and then fill with jam. The next day, glaze the orange cookies diagonally with warmed chocolate icing.