In the bowl of a stand mixer fitted with a paddle attachment, or a handheld mixer, cream together butter, brown sugar, and white sugar for 5 minutes on medium speed until light and fluffy.
Once five minutes is over, add in egg and vanilla and mix until combined.
In a separate bowl, mix flour, baking soda, and salt, and mix until combined. Add these dry ingredients to the butter mixture on low speed, and mix until just combined.
Using a wooden spoon or spatula, mix in chocolate chips or chunks until just combined. Place bowl of dough in fridge for at least 30 minutes to chill. Meawhile, preheat the oven to 350F (180C).
Form heaped cookie dough balls (about a 3 inch scoop or 3 tablespoon each), then flatten each ball and place one pistachio kunafa disk in the center of each. Wrap the dough around the kunafa, making sure to seal tightly. If you need to, add more dough to fully encircle the kunafa.
Place dough balls at least 2 inches apart on parchment paper lined baking sheets. I like to top each with a few more chocolate chips for visual appeal. Bake for 13-14 minutes or until light golden brown on the edges and set in the center. Don't overbake! Start checking at 12 minutes. If baking more than one sheet at once, swap their places in the middle of baking time.
Remove from the oven, sprinkle with a little flaky sea salt, let cool for a few minutes then enjoy!