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

In a large mixing bowl, whisk together the flour, pistachio pudding mix, baking soda, and salt.

In a separate bowl, cream together the softened butter, granulated sugar, and light brown sugar until light and fluffy.

Beat in the egg and vanilla extract. If desired, add a few drops of green food coloring.

Gradually add the dry mixture to the wet mixture, mixing until just incorporated.

Fold in the white chocolate chips and chopped pistachios.

Scoop out balls of dough, placing them 2-3 inches apart on the prepared baking sheets.

Bake for 10-12 minutes until the edges are lightly browned and the centers are soft.

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