Beat the amaretti with the egg whites, sugar, salt and vanilla sugar until stiff, then mix in the bitter almond oil and almonds. Fill the mixture into a piping bag with a round nozzle. Pipe small biscuits onto a prepared baking tray, sprinkle with powdered sugar and leave to dry for approx. 5 hours.
Bake the amaretti in the preheated oven at 165 to 175 °C for 10 to 12 minutes until light brown on sight. Store in a tightly closed container.