Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the peanut butter and sugar, mixing until well blended.
Add the egg, vanilla extract, baking soda, and salt, and stir until the dough is smooth.
Using a tablespoon, scoop out dough and roll it into balls.
Place the dough balls on a baking sheet lined with parchment paper, spacing them about 2 inches apart.
Use your thumb to make an indentation in the center of each cookie.
Spoon about 1/2 teaspoon of fruit preserves into each indentation.
Bake for 10-12 minutes or until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
