In a grinder, blend 60g pistachios with the seeds of 4–5 cardamom pods until coarse but spreadable. Set aside.
In a mixing bowl, beat 100g softened butter with 55g brown sugar and 50g sugar until light and fluffy.
Add the pistachio-cardamom paste, 1 tsp vanilla extract, and 1 tsp rose essence (if using). Mix well.
Beat in 1 room-temperature egg until smooth.
Sift together 160g flour, 12g cornstarch, ½ tsp baking soda, and a pinch of salt. Fold this into the wet mix using a spatula.
Stir in 30g chopped pistachios and 125g chopped dark chocolate.
Portion the dough into 12 balls. Place on a parchment-lined tray, press some chocolate chunks on top, cover, and refrigerate 2 hours or overnight.
Transfer chilled cookie balls to a parchment-lined baking tray with space between. Bake in a preheated oven at 180°C/350°F for 9–10 minutes, until cookies look matte with slightly browned edges.
Cool completely: Leave cookies to cool on the tray (they’ll firm up as they set).
