In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy, about 3-4 minutes.

Add the vanilla extract and mix until well combined.

In a separate bowl, whisk together the all-purpose flour and salt.

Gradually add the flour mixture to the butter mixture, mixing on low speed until just combined.

If the dough feels too soft, refrigerate for 15-20 minutes.

Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper.

Roll the dough into 1-inch balls, then roll each ball in coarse sugar.

Place the balls about 2 inches apart on the prepared baking sheets.

Using your thumb or the back of a small spoon, make an indentation in the center of each cookie.

Spoon about 1/2 teaspoon of fruit jam into each indentation.

Bake in the preheated oven for 12-15 minutes, or until the edges are lightly golden.

Remove from the oven and let the cookies cool on the baking sheet for 5 minutes.

Transfer them to a wire rack to cool completely.