Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a large bowl, cream together the softened unsalted butter and granulated sugar until light and fluffy, about 3-4 minutes.
Add the vanilla extract to the butter and sugar mixture and mix until combined.
In a separate bowl, whisk together the all-purpose flour and salt.
Gradually add the flour mixture to the butter mixture, mixing until a soft dough forms.
Divide the dough in half. Roll each half into a log about 1.5 inches in diameter.
Wrap the dough logs in plastic wrap and refrigerate for 30 minutes to firm up.
Remove the dough from the refrigerator and slice each log into 1/4-inch thick rounds.
Place half of the rounds on the prepared baking sheets.
Place a small teaspoon of raspberry jam in the center of each round on the baking sheets.
Top each jam-topped cookie with another round of dough, gently pressing the edges to seal.
Bake the cookies in the preheated oven for 18-20 minutes or until the edges are lightly golden.
Remove from oven and allow the cookies to cool on the baking sheets for 5 minutes before transferring to a wire rack to cool completely.