For the custard flowers, prepare the shortcrust pastry as described in the basic recipe.
Preheat the oven to 170° C hot air.
Roll out the dough on a work surface sprinkled with flour. Cut out flowers. Poke a hole in half of the cookies.
Place the cookies on a baking sheet lined with baking paper and bake for about 12 minutes.
In the meantime, prepare the custard: Prepare pudding according to package directions and stir in cold water bath until cold and no skin forms.
Cream butter with powdered sugar until fluffy. Stir the cold pudding into this mixture. If desired, refine with a little eggnog.
Let cookies cool and spread custard on cookie bottoms. Sprinkle confectioners’ sugar on top of cookies with hole. Place the sugared cookies on top of the cream coated ones.