Preheat your oven to 350°F (175°C).
In a medium bowl, whisk together the all-purpose flour, baking soda, and fine sea salt.
In a large mixing bowl, cream together the softened butter, light brown sugar, and granulated sugar until light and fluffy.
Add the instant pistachio pudding mix, eggs, and vanilla extract to the butter-sugar mixture. Beat until well combined.
Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until just combined.
Fold in the white chocolate chips and roughly chopped pistachios until evenly distributed.
Using a cookie scoop, drop heaping tablespoons of dough onto lined baking sheets, leaving space between each cookie.
Bake for 10-12 minutes, or until the edges are lightly golden.
Let cookies cool on the baking sheets for about 5 minutes before transferring them to a cooling rack.