Cream 1 cup of softened unsalted butter and 3/4 cup of granulated sugar in a large mixing bowl for about 3 minutes until light and fluffy. Add 1 large egg and 1 teaspoon of vanilla extract, mixing until smooth. Gradually incorporate 2 cups of all-purpose flour, 1/2 cup of powdered sugar, and a pinch of salt until a soft dough forms, being careful not to overmix.

Warm about 1/2 cup of raspberry jam gently in the microwave until easier to spread. For fresh raspberries, purée 1 cup, strain, and sweeten if desired to create the raspberry swirl.

On a floured surface, roll out the dough into a rectangle about 1/4 inch thick. Spread the raspberry swirl evenly over the dough, leaving a small border. Roll the dough into a log shape and seal the edges.

Wrap the log in plastic wrap and refrigerate for at least 1 hour. This step firms up the dough for easier slicing.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Slice the log into 1/4 inch thick rounds and arrange on the baking sheet. Bake for 10-12 minutes or until the edges are lightly golden.

Let the cookies cool on the baking sheet for about 5 minutes before transferring to a wire rack to cool completely.