In a big bowl, ix the two types of lour, sugar, salt. Cut the butter into small cubes and mix in the bowl to form crumbs. Add the egg yolk and formulate the dough.
Refrigerate the dough for about 30 minutes.
Preheat the oven for 180 Celsius.
On a floured surface, rollout the dough to 3 mm, using a rolling pin or an empthy wine bottle. Cut the dough to designed shape with cookie cutters or using a glass.
Line a baking sheet with parchment paper, and bake the cut Linzers for 7 to 10 minutes, keeping an eye on them as they burn easily.
Use half a teaspoon of the jam to stick together two cookies. Sprinkle with sugar if you like.