Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper and set aside.

In a large mixing bowl, cream the softened butter and powdered sugar together until light and fluffy. Add the vanilla extract and mix well.

Sift the all-purpose flour and salt into the butter mixture. Mix until the dough comes together. Do not overmix; just mix until the ingredients are combined.

Take small portions of the dough and roll them into 1-inch balls. Place the balls onto the prepared baking sheet, leaving some space between each cookie.

Use your thumb or the back of a small measuring spoon to make a deep indentation in the center of each cookie. Make sure not to press too hard; you just want to create a well for the jam.

Spoon a small amount of strawberry jam into the indentation of each cookie. Be careful not to overfill, as the jam will spread while baking.

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.

Once baked, remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes. Then transfer them to a wire rack to cool completely. The jam will set as the cookies cool.