Spread and Roll: Spread a thin, even layer of the jam mixture over each dough rectangle, leaving a small border around the edges. Starting from the long side, carefully roll the dough into a tight log, using the parchment paper to guide you and keep the roll compact.
Chill Thoroughly: Wrap each dough log tightly in plastic wrap. Refrigerate for at least 2 hours, or freeze for about 30 minutes. This chilling step is essential — firm dough ensures clean slices and well-defined spirals.
Slice the Cookies: Preheat your oven to 350°F (175°C). Remove the chilled dough from the refrigerator and use a sharp knife to slice the log into ½-inch thick rounds. Rotate the log as you slice to keep the shape round.
Bake: Arrange the cookies about 2 inches apart on parchment-lined baking sheets. Bake for 10–12 minutes, until the edges are just barely golden and the centers are set. Avoid overbaking to preserve the buttery shortbread texture.
Cool: Allow the cookies to cool completely on the baking sheet. They will continue to firm up as they cool, resulting in a crisp edge and tender center.
