Knead 225 g flour, icing sugar, 2 tablespoons water and margarine in flakes first with the dough hooks of the mixer and then with your hands briefly to a smooth dough. Cover and chill for about 1 hour.
Boil down coconut milk, syrup, sugar and lemon peel in a pot for about 3 minutes until creamy. Stir in grated coconut and cardamom, let cool down. Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Line a baking tray with baking paper. Roll out the dough onto some flour in a square (approx. 30 x 30 cm) and place on the baking tray. Prick the dough sheet more often with a fork. Spread the coconut mixture on it and press it down lightly. Bake in a hot oven for about 20 minutes until golden brown. Let it cool down.
Cut coconut slices into approx. 35 rhombuses (each side length approx. 5 cm). Break chocolate into pieces and melt in a hot water bath. Dribble thin chocolate strips over the cookie rhombs. Leave to dry.