About 50 cookies 
 
Ingredients:
250 gr. sifted flour
125 gr. confectioner's sugar 
1 large egg 
150 gr. cornflour 
250 gr. cold butter
Lemon zest from one lemon 
Pinch of salt 
 
For filling and garnish:
Nutella spread, 350 gr. 
Garnish with hazelnut croquant shavings  
 
Directions:
  1. Work all the ingredients into a uniform dough and refrigerate overnight.
  2. Roll out the dough and cut into round cookies in a baking trays lined with baking paper.
  3. Whip the egg and brush onto the top of the cookies.
  4. Garnish the cookies with hazelnut shavings.
  5. Bake in the oven for 10 minutes at 150 degrees and let the cookies cool down after baking.
  6. Spread a generous amount of Nutella on half the quantity of cookies and press two cookies together to make a sandwich.
  7. Refrigerate in a sealed container.