Preheat your oven to 350°F (175°C).
In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Add the egg and vanilla extract to the mixture and beat until well combined.
In another bowl, combine the flour and salt, then gradually add to the wet mixture, stirring until just blended.
Scoop tablespoon-sized balls of dough and place them on ungreased baking sheets, spacing them about 2 inches apart.
With your thumb or the back of a spoon, gently press down in the center of each cookie ball to create an indentation.
Fill each indentation with your chosen fruit jam, being careful not to overfill.
Bake in the preheated oven for 12-15 minutes, or until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.