1. In a large bowl, cream together butter and sugar until light and fluffy.

2. Add egg yolks and vanilla extract; mix until combined.

3. Gradually add flour and salt, mixing until a dough forms.

4. Roll tablespoon-sized portions into balls and place on a parchment-lined baking sheet.

5. Use your thumb or back of a spoon to make an indent in the center of each cookie.

6. Fill each indent with about 1/2 teaspoon of raspberry jam.

7. Bake at 350°F (175°C) for 12–14 minutes, until edges are lightly golden.

8. Cool on pan briefly, then transfer to a wire rack to cool completely.

9. Once cooled, dust with powdered sugar if desired.