Preheat the Oven: Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper.
Prepare the Dough: In a mixing bowl, cream together the softened butter, sugar, and vanilla extract until light and fluffy. Slowly incorporate the flour and salt, mixing well until combined.
Shape the Cookies: Divide the dough into small portions and shape them into 1-inch balls. Place them on the prepared baking sheets, leaving some space between each.
Create Thumbprint Indentations: Use your thumb or the back of a teaspoon to make an indentation in the center of each cookie. Be gentle to avoid cracking the dough.
Fill with Preserves: Spoon a small amount of your favorite fruit preserves into each indentation, adding a burst of fruity flavor to each cookie.
Bake: Bake the cookies in the preheated oven for 12-15 minutes or until the edges are lightly golden. Keep an eye on them to prevent over-baking.
Cool: Let the cookies cool a bit on the baking sheets before moving them to a wire rack to cool completely.