Christmas Ischler Cookies

For the cookies:

1. Blend the butter and sugar on high speed for 5-7 minutes or until the sugar has dissolved completely.
2. Add the egg yolk and vanilla essence and continue mixing.
3. Stir in the sifted flour and grated walnuts. You will get a crumbly dough. Shape it into a ball and refrigerate for 30 minutes.
4. Preheat the oven to 180°C/356° F and line a large baking pan with parchment paper.
5. Once chilled , transfer dough to a floured surface and roll it out into a 0.5 cm (1/5 of an inch) thick sheet.
6. Cut out 4-6 cm (1 ½ - 2 ½ inch) diameter circles and transfer them to a baking pan lined with parchment paper.
7. Bake the cookies for 12-15 minutes or until the edges are lightly brown.
8. Allow the cookies to cool completely before filling with cream.

For the chocolate cream:

1. Put the sugar and water in a saucepan. Melt the sugar over medium heat, then add the chopped chocolate.
2. Take the saucepan off the heat, let it cool for a few minutes, then add the egg yolk and mix well with a whisk. Allow the cream to cool completely before proceeding to the next step.
3. Blend the butter for 1 minute, then fold in the chocolate cream, mixing constantly.

For the chocolate glaze:

1. Melt the chopped chocolate in a steam bath and add two tablespoons of oil. The oil will give the glaze a very nice shine.

Assembly:

1. Cover half the cookies with the chocolate glaze. Place the cookies on a rack over a cooking sheet and spoon the glaze onto the center of each cookie, making sure it covers the entire surface and the sides. Place a half walnut in the middle of each one.
2. Place the cookie rack in the freezer for a few minutes until the glaze hardens completely.
3. Pour the chocolate cream into a piping bag and pipe it onto the bottom side of the unglazed cookies.
4. Place a glazed cookie on top of a creamed cookie and decorate with walnuts.

Serving and storage:

1. The cookies can be served immediately after baking or can be stored for a few days in the fridge in a food contained with a lid.