Melt 1 teaspoon of unsalted butter in a large saucepan over low heat.

Tear the filo pastry into small pieces and add to the saucepan.

Stir the filo over medium heat until crunchy, golden, and toasted, about 5 minutes. Remove from heat and transfer to a bowl.

Microwave the pistachio cream for 10-20 seconds until melted and smooth. Pour over the toasted filo (reserve 2 tablespoons for decoration) and stir until well coated. Set aside to cool.

Chop the butter into chunks and place in a large mixing bowl. Beat until soft and broken up.

Mix in the light brown sugar and white caster sugar until combined.

Add the eggs to the mixture and combine.

In a separate bowl, whisk together the self-raising flour, plain flour, cocoa powder, and salt. Fold into the butter mixture to create a thick cookie dough.

Fold in the milk chocolate chips.

Line a baking tray with greaseproof paper. Break off large heaped tablespoons of cookie dough, flatten, and place a teaspoon of pistachio filling in the center. Wrap the dough around to form a ball. Repeat until all dough is used (makes 12 cookies).

Place the cookies on the baking tray and wrap tightly in foil. Freeze for 90 minutes.

Preheat the oven to 200°C fan / 220°C conventional. Line a large baking tray with greaseproof paper and preheat for 5 minutes.

Bake 4-5 frozen cookies on the preheated tray for 12-15 minutes until firm on the edges but soft in the middle. Allow to cool on the tray for 15 minutes.

Decorate by microwaving the reserved pistachio cream for 10-20 seconds, stirring until smooth. Pipe or drizzle over the cookies before serving.