First, freeze the pistachio creme. Different brands vary in texture, so you may wish to pipe rather than spoon (using a teaspoon) the mounds onto a sheet of baking parchment, then pop in the freezer for about 1 hr. Each mound should be about the size of a teaspoon.

Cream the butter, all the sugar and vanilla together in a stand mixer using the paddle beater, an electric hand whisk, or just by hand with a wooden spoon in a big mixing bowl, until pale and fluffy. Beat in the egg until combined. Tip in the flour and baking powder, then mix slowly until combined and you have a sticky dough. Fold in the chocolate chips and pistachios.

With damp hands to prevent the dough sticking, break into 12 pieces (weighing 60g-70g each) then roll into balls. Flatten each to a large puck then add the frozen mounds of pistachio cream to the centre. Carefully wrap the cookie dough around the cream, shaping it back into a ball to seal, then pop into a container lined with baking parchment, or on a lined baking tray and put in the fridge to chill for a few hours. Will keep chilled overnight. Once set firm, you can also freeze the cookies in a bag – just bake for a little longer than chilled.

When ready to bake, heat the oven to 200C/180C fan/gas 6. Line a couple of baking sheets with baking parchment and arrange the balls of dough between them, well spaced apart. They will spread a lot in the oven.

Bake for 10-12 mins until the cookies are lightly golden around the edges but are still very squidgy in the centre. Halfway through baking, take the sheet out and give it a tap on your work surface. (They should be going golden on top and around the edges but still wobbly in the middle.) Leave to cool on the tray for a few minutes before eating while the chocolate is just a bit melty. These make a great pudding if you serve them with a scoop of ice cream, too.