Fit the Whisk tool to the machine.
Line the baking tray with parchment paper.
Add Ingredients 1 (sugar, yolks) into the medium bowl.
Mix until combined.
Add Ingredients 2 (whites, salt) to the Mixer bowl.
Attach the Mixer bowl to the machine and fit the splash guard.
Mix on speed Max for about 1 minute until stiff peaks form.
Transfer the sugar mixture into the Mixer bowl.
Mix on speed 3 for 2 minutes.
Remove the Whisk and fit the K beater.
Add Ingredients 3 (lemon zest, baking powder, kirsch, flour) into the Mixer bowl.
Mix on speed Min for 3 minutes.
Cover the bowl.
Leave to rest for 1 hour.
Transfer the dough to a lightly floured surface.
Divide the dough into quarters.
Roll out the dough until 1 cm thick.
Dust both sides of the dough with Ingredients 4 (cornflour).
Either roll the springerle rolling pin over the dough, pressing firmly OR press the moulds firmly into the dough.
Cut out the biscuits.
Place them on the baking tray and cover.
Leave to rest overnight.
Pre heat the oven to 140ºC.
Bake for 30 minutes at 140ºC.
Leave to cool on a wire rack.
Serve.