Put 100 g sugar, orange zest, 1 pinch of salt, 175 g flour, polenta and margarine in flakes in a mixing bowl. Mix briefly with the dough hooks of the mixer, then knead with your hands to a smooth dough.
Form into a flat ball, cover and chill for about 1 hour.
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Line two baking trays with baking paper. Knead the dough briefly, then roll out to a thickness of just under 5 mm on a floured work surface. Cut into rectangles (approx. 3.5 x 5 cm each), kneading, rolling out and cutting out dough remains again and again.
Distribute on the sheets with a distance of about 2 cm. Prick three times with a fork in each case. Bake in a hot oven for about 10 minutes.
Take out and immediately sprinkle with 2 tablespoons of sugar. Leave to cool on the trays for about 10 minutes. Let it cool down on a cake rack.