In a bowl, cream together the softened butter and sugar until light and fluffy.
Beat in the egg until well combined.
Gradually add flour and salt, mixing until a dough forms.
Divide the dough in half and roll each half into a log.
Spread raspberry jam on one log and press the other log on top, then twist them together to create a swirl pattern.
Chill the wrapped dough in the refrigerator for at least an hour.
Preheat your oven to 350°F (175°C).
Slice the chilled dough into cookies and place them on a baking sheet, leaving space between each cookie.
Bake for 12-15 minutes, or until the cookies are lightly golden on the edges.
Let them cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.
