Preheat oven to 300 degrees. Line a 9x13 inch pan with aluminum foil or parchment paper for easy removal.
In a large bowl combine the flour and sugar and beat in the butter until combined. Press into the bottom of the pan and bake for 30-35 minutes or until the crust is lightly golden brown on the edges. Remove from oven and let cool.
To make the pistachio layer beat together the cream cheese and powdered sugar until creamy. Add in milk and pistachio pudding and continue to mix until incorporated. Spread over the crust and refrigerate an hour until set. Top with roughly chopped pistachios.