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

Whisk together the flour and powdered sugar in a bowl until well combined.

Beat the unsalted butter in another bowl until creamy. Add the egg yolks and vanilla extract, mixing until light and fluffy.

Incorporate the dry ingredients gradually into the butter mixture. Stir until a soft dough forms.

Divide the dough into two portions, wrap each in plastic wrap, and refrigerate for one hour.

Roll out one portion of dough on a floured surface to about 1/4 inch thick using heart-shaped cookie cutters.

Place the cookies on the prepared baking sheets and bake for 10-12 minutes until lightly golden.

Allow them to cool completely before spreading jam on the solid cookies and topping with the cutout cookies.

Dust with powdered sugar for an extra touch of sweetness (optional).