Finely chop 3/4 cups of pistachios. Trim the ends off the green beans.
Add to the boiling water and cook until tender, just about 5 minutes. Drain them into an ice bath to ensure they stop cooking. Once they are cooled, transfer them to a clean kitchen towel to dry them.
Finely grate the garlic cloves and zest of 1 lemon into a medium bowl. Add the juice of the lemon. Slowly whisk in the olive oil.
Whisk in the parmesan cheese and then the chopped pistachios. Season with salt and pepper.
Add the green beans to the bowl and mix until completely dressed. Transfer to a serving platter. Serve cold and delicious!