Beat together the butter and cream cheese.
Add sugar and beat until fairly light and fluffy.
Keep beating with medium speed and add the egg yolks, lemon extract and salt. Mix until well combined.
Beating on low speed, slowly add flour. Mix until the flour is incorporated. The dough will be very soft.
Preheat oven to 160°C and line a baking sheet with parchment paper.
Scoop out a good portion of dough and place on a floured surface. Dust with extra flour and roll out dough (about 1cm). Dust again and, using the engraved rolling pin, roll once over dough, pressing down lightly. The dough will now be ca. 0,5cm think and the pattern will be engraved in the dough.
Cut out circles and place on prepared baking sheet.
Bake ca. 10-12 minutes.
Take out of the oven and place carefully on a wire rack to cool.
This makes 80-120 cookies, depending on the size of the cookies. You can half the recipe.