Biscuits: Sift flour onto a work surface and form a hollow in the flour mound. Sprinkle sugar into the hollow. Pour egg into the hollow. Cut the butter into small pieces and place them around the edge of the flour. Now sprinkle the almonds over it and chop everything together with a knife. Knead the resulting crumble into a smooth dough with cool hands. Cover and chill for 1-2 hours.
Roll dough into 2cm thin rolls and cut into 1cm lengths. Shape each piece into a small crescent and place onto a baking tray.
Preheat oven to 220 degrees C. Bake in the preheated oven for about 10 minutes.
Rolling: Mix vanilla seeds and icing sugar and place on a plate. Roll the crescents in the vanilla sugar while still warm. When cool, store in an airtight tin.