For the Linzer Kipferl, sift the flour, cornflour, vanilla sugar and powdered sugar onto a pasta board and spread the butter cut into strips over it.
Add the egg yolk and milk as needed to make a nice dough.
Leave to rest for one hour. Then pour into a piping bag and pipe even crescents onto a baking sheet.
Bake in the oven at 170 degrees for about 10 minutes. Spread apricot jam on the inside of each croissant and place a second one on top. Melt chocolate icing and dip the top of each Linzer Kipferl.