01 -
Preheat the oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, leaving overhang on two sides, and lightly grease the exposed sides.
02 -
Beat the softened butter, brown sugar, kosher salt, and vanilla until creamy and smooth, about 2 minutes. Add the flour and mix on low just until the dough looks sandy and clumps when pressed.
03 -
Transfer the dough to the prepared pan. Press it into a firm, even layer, using the bottom of a measuring cup to compact the surface and corners.
04 -
Bake for 28-32 minutes, until the edges are golden and the center looks set. Remove the pan from the oven but leave the oven on.
05 -
Sprinkle the chocolate chips evenly over the hot shortbread. Return the pan to the oven for 1-2 minutes, just until the chips look glossy and soft, then spread them into an even layer.
06 -
Scatter the chopped candy over the melted chocolate. Press lightly so the pieces stick, then add a small pinch of flaky salt if using.
07 -
Cool the bars at room temperature for 30 minutes, then refrigerate until the chocolate is firm, about 45 minutes. Lift out with the parchment and cut into 16 bars.