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

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy, about 2-3 minutes.

Add in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Add in the lemon zest and lemon juice, mixing until incorporated to create a soft dough.

Divide the dough in half and place one half in another bowl. Stir in the raspberry jam into one half of the dough until it's fully mixed. Leave the other half plain.

Roll out both portions of dough on a lightly floured surface until about ¼ inch thick.

Carefully layer the raspberry dough on top of the plain dough. Roll the two doughs together gently to create a swirl effect.

Cut the rolled dough into 1-inch pieces and place them on the prepared baking sheet, leaving some space in between.

Bake in the preheated oven for 10 minutes, or until lightly golden around the edges.

Remove from the oven and let the cookies cool on the baking sheet for a few minutes before transferring them to a cooling rack.

For added flavor, you can sprinkle some powdered sugar on top of the cookies once they're cooled.

Store any leftover cookies in an airtight container at room temperature for up to a week.