Cream together the butter and granulated sugar until light and fluffy.

Add the vanilla extract and mix well.

Gradually add the all-purpose flour and salt, mixing until just combined.

Shape the dough into small balls and place on a baking sheet lined with parchment paper.

Make an indentation in the center of each ball using your thumb or a small heart-shaped tool.

Fill each indentation with your choice of jam.

Bake in a preheated oven at 350°F (175°C) for about 12 minutes or until lightly golden.