Preheat oven to 350°F (175°C) and line baking sheets with parchment paper.

In a bowl, cream together the softened butter and granulated sugar until fluffy. Mix in the egg yolk and vanilla extract until well combined.

Gradually add both flours until a smooth dough forms.

Roll out half of the dough to about 1/8 inch thick and cut out cookie shapes, ensuring you have matching tops for each bottom cookie.

Bake for 10-12 minutes or until lightly golden around the edges. Allow them to cool completely on wire racks.

Spread jam on the bottom of each cookie and sandwich with the top cookie. Drizzle icing over each assembled cookie.