• MAKE DOUGH: Place 300g (¾) of the hazelnuts in a mixing bowl with all the other dough ingredients and use your hands or a wooden spoon to knead to a smooth dough. When the dough is smooth and pliable after 3-4 minutes, flatten it into a disk, wrap it in cling film and place it in the fridge for 1 hour.
• ROLL DOUGH: After an hour, remove the dough from the fridge and roll it out to 1 cm (just more than 1/3 in.) thickness on either a work surface sprinkled with ground nuts or in a large freezer bag with the long sides cut open. Return to the fridge (or freezer if your freezer is big enough!) while you prepare the frosting.
• PREPARE AND MAKE FROSTING: Heat the oven to 120°C / 250°F / Gas ½ and line two oven trays with baking parchment paper. In a clean bowl using an electric beater, beat the egg white and lemon juice until it is light and fluffy. Add the powdered sugar 1 tablespoon at a time until it is completely incorporated. Continue beating for 4-5 minutes until the mixture is thick and glossy.
• CUT COOKIES: Remove the cookie dough from the fridge or freezer and cut as many star shapes as possible with an approx 4cm (1.5 in.) star-shaped cutter. Place them on the prepared baking sheets as you go. Re-roll the cookie dough to cut out as many as possible, adding some of the reserved ground nuts as necessary.
  
• FROST COOKIES: Use a spoon or pastry brush to spread a thick layer of the frosting on the top of the cookies, then bake, one tray at a time on the bottom shelf of the oven for 20 minutes.
  
• COOL: Allow to cool on the tray for 5 minutes before transferring to a rack to cool completely. Store in a metal cookie tin (not an airtight container!) for up to 4 weeks.

Alternative Frosting Method:

• If you fancy a really professional finish on your Zimtsterne and have a large freezer space, remove the dough from the fridge, spread it thickly with the frosting, smooth the surface then place it in the freezer for two hours. Remove from the freezer and use a star-shaped cutter to cut out as many stars as possible, placing them on the baking trays as you go. I find it easier to push the stars through the cutter from the bottom, however, the dough and frosting should be firm enough to handle easily from their time in the freezer.
• Any remaining offcuts can either be cut into small pieces and baked as is, but I like to re-roll it with the reserved ground nuts and repeat the process. Bake the cookies, one cookie sheet at a time, on the bottom shelf of the oven for 25 minutes, allow to cool on the tray for 5 minutes then transfer to a rack to cool completely before storing.