In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the sour cream and vanilla extract, mixing until well combined.

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

Wrap the dough in plastic wrap and refrigerate for at least 1 hour.

Preheat the oven to 350°F (175°C).

On a floured surface, roll out the chilled dough to about 1/8 inch thick.

Cut into squares or circles using a cookie cutter.

Place a small spoonful of fruit preserves in the center of each piece.

Fold the corners of the dough over the filling to create a pocket, pinching to seal.

Place on a baking sheet lined with parchment paper.

Bake for 15-20 minutes or until lightly golden.

Allow cookies to cool slightly on the baking sheet.

Dust with powdered sugar before serving.