Ingredients:
Dough:
400 g all-purpose flour (about 3.2 cups)
100 g cornstarch (about 3/4 cup)
2 eggs
100 g powdered sugar (about 3/4 cup)
16 g vanilla sugar (about 1 tablespoon)
250 g cold butter, diced (about 1 cup)
1/2 tsp baking powder
Filling:
1 cup milk
1/2 cup sugar
3 egg yolks
a pinch of salt
3 tbsp all-purpose flour
230 g softened butter (about 1 cup)
3 tsp nut liqueur, rum, or vanilla extract
1/2 cup ground walnuts
Combine the dough ingredients in a mixing bowl.
Or work by hand: cut the butter into the flour, add the remaining ingredients, and knead until the dough comes together.
Chill the dough in the refrigerator for 30 minutes.
Form small balls from the chilled dough and bake the cookies.
For the filling:
Mix the milk with half of the sugar and bring it to a boil.
In a mixing bowl, whisk the egg yolks, salt, the remaining sugar, and vanilla until pale.
Add the flour and whisk again.
When the milk comes to a boil, pour one third of it into the egg yolk mixture and whisk.
Return this mixture to the pot with the milk and cook until it thickens to a pudding-like consistency.
Remove from the heat and cover with plastic wrap, pressing the wrap onto the surface of the custard to prevent a skin from forming.
Let the custard cool.
Beat the butter until fluffy.
Gradually add the cooled custard to the butter, one spoonful at a time, while continuing to beat.
Fold in the ground walnuts.
Fill the cookies with the cream.
