Line a baking tray with cling film. Place 8 generous teaspoonfuls of pistachio cream on the cling film, then pop the tray in the freezer to chill for at least a half hour.

In a large mixing bowl, cream together butter and sugars until smooth and paler. Add in vanilla and mix through. Sift in the flour, cornflour, cocoa, baking powder, bicarbonate of soda (baking soda) and salt. Mix until the mixture is evenly combined and is damp but not clumping. Stir in most of the chocolate, then tip in the egg and mix until everything is starting to clump together.

Divide the cookie dough evenly into eight portions, then roll each portion into balls and flatten in the palm of your hand. Place one of the frozen pistachio spoonfuls in the middle of the cookie dough, then wrap it around the cream, sealing completely. Roll it into a ball, ensuring the pistachio cream is completely sealed within the cookie dough, then repeat with the remaining dough. Stud with the additional chocolate chunks, then place the balls on the baking tray and back in the freezer. Chill for at least eight hours.

When you are ready to bake, prepare another baking sheet with some parchment paper and preheat the oven to 180C/350F. Place the cookies spaced apart on the tray to allow for spreading during baking. I get four to a tray for when I am baking these cookies.

Place the tray in the hot oven and bake the cookies for 11-14 minutes until the edges are firm and lightly crisp. Leave the cookies on the baking tray to cool for at least 20 minutes. The cookies will be thick and soft when fresh from the oven, but will firm up as they cool.

Once the cookies have cooled, warm a little extra pistachio cream and drizzle it over part of each cookie. Sprinkle with some chopped pistachios to finish. Enjoy!