Whisk flour and salt in a small bowl and set aside.
Mix sugar and softened butter. Do not over mix.
Add eggs one at a time and mix.
Combine until dough ball forms in mixer.
Divide dough in half and wrap in plastic wrap.
Refrigerate for two hours.
Roll dough between two sheets of parchment paper.
Place in freezer for 10 minutes. This will firm up the rolled dough.
Dip cookie cutters in flour and cut out cookie shapes.
You'll need two cookies to complete each cookie.
Cut smaller shape in the center of a cookie mate.
Bake for 8 minutes until edges are lightly browned.
Allow cookies to cool completely.
Spread jam across one cookie.
Place the cookie with the cutout center on top of the jam-spread cookie and press gently.
Dust completed cookie with confectioner's sugar.
I have found that these cookies are their most flavorful when refrigerated overnight. There's just something about getting that overnight nap that really infuses Linzer cookies with more sweet and fruity taste.