Line a plate with parchment paper and pour the pistachio spread on top, spreading it into a thick sheet. Freeze for at least 1 hour or overnight until solid.

Get a cutting board or plate lined with parchment paper for chilling your cookie dough. Set it aside.

In a small bowl, mix the flour, cornstarch, baking powder, baking soda, and salt. Set aside.

In a larger mixing bowl, combine melted butter, brown sugar, and granulated sugar. Whisk until smooth.

Add in the egg and vanilla extract, whisk until combined.

Dump the flour mixture into the butter mixture and whisk until barely mixed, leaving some flour patches.

Gently fold in the chopped chocolate and pistachios using a spatula.

Use a 4-tablespoon scoop to form dough balls and place them on your lined board. Chill in the fridge for about an hour.

Preheat your oven to 350°F and line a baking sheet with parchment paper.

Flatten a dough ball, place your frozen pistachio cream in the center, and wrap the dough around it securely.

Place the stuffed balls on your baking sheet, adding extra chocolate chunks and pistachios on top.

Bake for 11-12 minutes until the edges are set but the centers are still soft. Sprinkle with flaky salt and let cool for 5 minutes.