Next, I cream the softened butter and powdered sugar until they’re light and fluffy, which usually takes a minute or two. I add vanilla and salt, then slowly mix in the flour. The dough may seem crumbly at first, but keep mixing—it will pull together into a soft, smooth ball. The moment it does, I divide it into two equal portions, which makes it easier to roll later.
I spread a sheet of plastic wrap on the counter, place one portion of dough on it, and shape it into a rough rectangle with my hands. Then I lay another sheet of wrap on top and use a rolling pin to gently roll it into a ¼-inch thick rectangle. Spreading the cooled raspberry filling over it is always my favorite part; the contrast of the creamy dough against the vibrant red filling is so pretty. I leave a small border at the edges to prevent the filling from squeezing out when rolling.
Using the bottom piece of plastic wrap to help guide it, I roll the dough into a tight log, making sure the swirl stays even from end to end. Once the log is wrapped securely, I chill it for at least two hours—overnight is even better. When I’m ready to bake, I slice the log into cookies about ¼–½-inch thick and arrange them on a parchment-lined baking sheet before baking them until the edges just start to turn golden.
Pro Tips for Best Results
I tested this recipe three different ways—rolling the dough thick, rolling it thin, and rolling it somewhere in between—and I learned that ¼-inch thickness is the sweet spot for the perfect swirl and ideal shortbread texture. Thicker dough overwhelms the filling, while thinner dough tears easily and doesn’t hold shape.
Here’s something I learned the hard way: the raspberry filling must be completely cooled before spreading it on the dough. I once tried to speed through the process and spread slightly warm filling, and it softened the butter in the dough so much that rolling became a mess. Trust me, patience pays off.
Chilling the rolled dough is absolutely essential. I’ve tried skipping or shortening this step out of curiosity, and the cookies spread too much and lost their beautiful spiral. Give the dough at least two full hours in the fridge so the butter resets and the swirl stays sharp during baking.
Another tip that makes a big difference is wiping the knife between slices. It seems tedious, but each swipe prevents raspberry streaks from dragging through the dough and keeps the swirl crisp. I also like using a serrated knife and cutting gently to avoid squishing the roll.
Common Mistakes to Avoid
I made the mistake of overcooking the raspberry filling once, thinking thicker was better, but it actually became too stiff and hard to spread. If you notice it getting excessively thick, remove it from heat immediately; it should still be spreadable but not runny.
Another common mistake is adding too much flour. Shortbread dough should feel soft and just barely hold together when pinched. If it’s dry and crumbly even after mixing, you may have packed the flour into the measuring cup. I always fluff the flour first, spoon it into the cup, and level the top.(See the next page below to continue…)