Prepare the Cookie Dough

• In a medium bowl, whisk together the flour, baking powder, and salt.
• In a large mixing bowl, beat the butter and sugar until light and fluffy (about 2-3 minutes).
• Add the egg and vanilla extract, mixing until combined.
• Gradually add the dry ingredients, mixing just until incorporated.

Make the Blueberry Cheesecake Swirl

• In a separate bowl, beat the softened cream cheese, sugar, and vanilla extract until smooth.
• Stir in the blueberry preserves, creating a marbled effect without overmixing.

Assemble the Cookies

• Roll out the cookie dough into a rectangle on a floured surface (about ¼-inch thick).
• Spread a thin layer of the blueberry cheesecake mixture evenly over the dough.
• Carefully roll the dough into a log, wrap it in plastic wrap, and refrigerate for at least 1 hour.

Slice and Bake

• Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.
• Slice the chilled dough into ½-inch thick rounds and place them on the baking sheet.
• Bake for 10-12 minutes, or until the edges are lightly golden and the centers are just set.
• Let the cookies cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.