Linzer Cookies

In the bowl of a food processor, combine both types of flour, salt, cold butter cut into pieces, and powdered sugar. Process until the mixture forms coarse crumbs.
Add the yolks, turn on the blender and wait until the dough comes together into a ball. You can also knead the dough by hand, first using a knife and then moving on to hand kneading. Don’t knead the dough for too long.
Wrap the dough in plastic wrap and chill in the refrigerator for 1 hour. You can also refrigerate the dough overnight. In this case, remove the dough about half an hour before rolling.
Preheat the oven to 180 °C.
Lay parchment paper (or perforated silicone mat, it’s preferable for the cookies) on a baking sheet.
Dust the table with flour. Roll the dough into plate of 2-3 mm thickness. Using a marble rolling pin makes this process easier because of the pin’s weight and its low temperature. While you roll out one portion of the dough, keep the rest in the fridge.
Cut out a cookie with a hole in the middle, then the same number of cookies without a hole. Put cookies on a baking sheet.
Bake cookies for about 10 minutes or until lightly browned.
Immediately after baking, the cookies will be very fragile. Wait a moment, then transfer the cookies to a wire rack and cool completely.
Dust gentle the holed cookies with sugar powder.
Use the jam to glue the hole cookies and the whole cookie in pairs. 1/3 teaspoon of jam is enough for each cookie.