Cut open the vanilla pod, scrape out the pulp. Separate egg. Cream butter, icing sugar, vanilla pulp and salt. Stir in egg yolk. Mix flour and starch and knead in. Form dough into 3 rolls (each approx. 30 cm). Cover and chill for about 2 hours.
Brush 2 dough rolls with egg white. Roll 1 roll in sugar, roll the other in brittle. Cut both rolls into approx. 1/2 cm thick slices. Spread the 3rd roll with egg white, then cut into approx. 1/2 cm thick slices and turn into flaked almonds. Put the biscuits on trays lined with baking paper. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3/ convection oven 175 °C) for about 10 minutes