Mix together the sugar, baking oil, lebkuchen spices and salt. Add the egg and sugar beet syrup and beat. Then add the ground almonds, flour and baking powder. Combine everything to form a homogeneous dough, wrap in a beeswax cloth and chill covered for at least 1 hour.
Roll the chilled dough out to approx. 2-3 cm thick on a well-floured work surface, cut out the lebkuchen one by one and place on a baking tray lined with baking paper, then bake at 170 °C in a fan-assisted oven for approx. 8-9 minutes. Once cooked through, allow to cool on a rack.
Whisk the egg white and stir in the icing sugar to produce a smooth, firm mixture. Split the mixture into portions and dye with food colouring, adding a little water if necessary. Add the finished icing to a small piping bag with a fine nozzle or fill a decorating pen and use the icing to decorate the lebkuchen.
Our tip: If you want to decorate with sharp lines, you will need firmer icing; for icing large areas, simply add a little water!