Freeze teaspoons of pistachio cream on parchment paper for 30 minutes until firm.
Cream softened butter with brown and white sugars until light and fluffy.
Add egg and vanilla extract to the butter mixture and mix until smooth.
In a separate bowl, whisk together flour, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients and mix until just combined.
Fold in chocolate chunks and chopped pistachios.
Take about 2 tablespoons of dough, flatten it, place a frozen pistachio cream piece in the center, cover with another dough piece, seal edges, and shape into a ball.
Chill the dough balls in the refrigerator for 30 minutes to maintain shape.
Preheat oven to 350°F (180°C). Arrange dough balls on a lined baking sheet spaced apart.
Bake for 11 to 13 minutes until edges are golden but centers remain soft.
Sprinkle coarse sea salt on warm cookies and allow to cool 10 minutes before serving.