Preheat your oven to 350°F (175°C) and line your baking sheets with parchment paper.

In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 3 minutes.

Beat in the eggs one at a time and then mix in the vanilla extract until well combined.

In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add this dry mixture to the wet ingredients, mixing until just combined.

Gently fold in the chopped pistachios (and chocolate chips, if using) until evenly distributed throughout the dough.

Using a cookie scoop or tablespoon, drop rounded mounds of dough onto the prepared baking sheets, leaving some space between each cookie.

Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden. The centers may look soft, but they will firm up as they cool.

Allow the cookies to cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.