Pound the cardamom seeds and sugar together using a pestle and mortar until the seeds are finely ground. Set aside. Tip the pistachios into a food processor and blitz until finely chopped.

Put the chocolate in a heatproof bowl. Tip the cream and ground cardamom mixture into a small pan and bring to a simmer over a low heat, stirring occasionally, for 2 mins until steaming. Slowly pour over the chocolate, whisking until the chocolate has melted.

Mix in the butter, 1 tsp at a time, until fully incorporated. Stir in 80g of the chopped pistachios, then cover the bowl and chill for 3-4 hrs to firm up.

Scoop the truffle mixture into marble-sized balls using a teaspoon, and gently roll each piece between your palms to shape. (You may want to wear gloves for this.) Arrange the truffles on a tray lined with parchment and chill for 30 mins to firm up.

Tip the remaining chopped pistachios onto a large plate and roll the truffles in them to evenly coat. Will keep chilled in an airtight container for five days. Serve at room temperature.