Stir together the flour, pudding mix, baking soda and salt. Set aside.
Beat the butter and both sugars together in a large bowl with a stand up mixer or hand held mixer until the mixture is creamy and light.
Add in the eggs and vanilla extract. Mix until all the ingredients are combined.
Gradually add the flour mixture into the egg mixture until just combined. Be careful not to over mix. Add in green food coloring until the dough is a deeper green color.
Gently stir in the white chocolate chips and crushed pistachios into the cookie batter by hand.
Drop the cookie dough by rounded tablespoons onto a baking sheet. Bake for 10-12 minutes until the cookies are slightly golden brown around the edges.
Remove the cookies from the oven. Press a few additional white chocolate chips into the tops of the cookies while they are warm.
Let them sit on the baking sheets for 5 minutes and then transfer the cookies to a wire rack to cool completely.
Notes
Store the leftover cookies in an airtight container at room temperature for up to 4-5 days. Keep a piece of bread in the container with the cookies to keep them moist.