Spooky Skull Jam-Filled Cookies with Chocolate Skeleton Faces

In a large mixing bowl with a stand mixer fitted with the paddle attachment, or with a hand mixer, beat the softened butter on medium speed for 2 minutes until pale, creamy, and spreadable.

Add the sifted powdered sugar and salt to the butter and beat on low speed for 1 minute to combine, then increase to medium and beat for 2 minutes until the mixture looks pale and fluffy.

Add the vanilla extract and beat briefly on low until just incorporated, about 30 seconds.

Whisk the flour and cornstarch together in a separate bowl. Add this dry mixture to the butter in three additions, mixing on low just until the dough comes together in soft clumps. Do not overwork the dough.

Turn the dough out onto a sheet of plastic wrap, press it into a 2 cm-thick disc, wrap tightly, and refrigerate for 1 hour until firm enough to roll without sticking.

Preheat the oven to 175°C (350°F) and line two baking sheets with parchment paper.

On a lightly floured surface, roll the chilled dough to an even 5 mm thickness.

Cut out 40 skull shapes with the cookie cutter and transfer them to the prepared baking sheets, spacing them 3 cm apart. Re-roll the scraps once, chilled briefly if needed, to cut the remaining skulls.

Bake one sheet at a time for 11-13 minutes, until the edges show a whisper of gold and the centers look matte and set. Rotate the pan front-to-back at the halfway point for even browning.

Let the cookies rest on the baking sheet for 5 minutes, then transfer to a wire rack and cool completely, about 20 minutes.

Place the chopped dark chocolate in a heatproof bowl set over a saucepan of barely simmering water - the bowl must not touch the water. Stir gently until two-thirds melted, then remove from heat and stir until completely smooth and glossy. Transfer to a piping bag fitted with the 2 mm round tip.

Pipe skeleton faces onto 20 of the completely cooled cookies (these will become the sandwich tops): two round hollow eye sockets, a small triangular nasal cavity, and a row of short vertical lines across the lower third for teeth. Let the chocolate set at room temperature for 15 minutes until firm to the touch.

Stir the seedless raspberry jam in its jar until smooth and glossy, then transfer to a clean piping bag or a small bowl.

Flip the remaining 20 cookies flat-side up. Pipe or spread about 9 g of jam onto each, leaving a 5 mm border around the edge. Top with a chocolate-faced skull cookie and press very lightly while giving the top a small twist so the jam spreads cleanly to the edges. Rest the assembled cookies for 10 minutes so the chocolate decoration firms up fully.

Serve the cookies at cool room temperature so the chocolate snaps cleanly against the tender crumb and the jam loosens to a saucy, jewel-like layer.