Syrup:
13g (about 0.5 oz) butter
25g (about 0.9 oz) sugar
37g (about 1.3 oz) milk
Dough:
syrup (prepared above)
200g (about 1.4 cups) flour
4 tablespoons powdered sugar
100g (about 3.5 oz) butter
1 egg yolk
For the syrup: Combine the butter and sugar in a small saucepan and bring to a boil. Add the hot milk and cook until the syrup thickens. Let the syrup cool to room temperature.
For the dough: Mix the flour, powdered sugar, butter, and egg yolk, then add the cooled syrup. Knead the dough well. Refrigerate the dough for 30 minutes.
Roll the dough out thinly, dusting with flour to prevent sticking. Cut out cookies, making half of them whole and the other half with a hole in the center. Place them on a baking sheet lined with parchment paper and bake at 200 degrees Celsius (about 400 degrees Fahrenheit) for approximately 10-15 minutes.
Let the cookies cool. Spread a thick layer of jam on the whole cookies and top them with the ones that have a hole. Dust with powdered sugar.
