1. In a medium bowl, whisk together the flour and salt.

2. In a large bowl, beat the softened butter and granulated sugar until light and creamy.

3. Mix in the egg yolk and vanilla extract until smooth.

4. Gradually add the flour mixture and mix just until a soft dough forms.

5. Shape the dough into a disk, wrap it, and chill for 45 minutes.

6. Preheat the oven to 350°F and line baking sheets with parchment paper.

7. Roll the dough to about 1/4-inch thickness on a lightly floured surface.

8. Cut out an even number of large heart shapes, then cut smaller hearts from the center of half of them.

9. Arrange the cookies on the baking sheets and bake for 10 to 12 minutes, until the edges are lightly set.

10. Cool the cookies completely on a wire rack.

11. Spread raspberry jam on each solid cookie base.

12. Top with the cutout cookies and dust with powdered sugar before serving.